Vertical Services Integration Enabled Content Distribution Mechanism
Claim Score by NHIP
Abstract
The invention relates to an enhanced ADSL Data Network (ADN) with vertical services capabilities. In general, vertical services capabilities are data services offered directly from a central office to an end user, without compromising the integrity of the user's guaranteed bit rate to the Internet through the ADN. One such vertical service is content downloadable at a high data rate from a content server located in or proximate to a central office that serves the end user. The content of the local server is updated and upgraded periodically and systematically from a central content server that distributes content to a number of remote central offices. The content is distributed between the central content server and the respective local content servers using available bandwidth, that is to say bandwidth on at least certain network links that is unused by subscriber traffic.

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20 claims: 2 independent, 18 dependent
- 1Broadest claimClaim Score 77, broad(NHIP)A method of replicating content data stored on a first server to at least one second server, comprising the steps:determining unused bandwidth on a common link of an access data network, carrying subscriber traffic and over which the first server and the at least one second server communicate;and transmitting content data stored on the first server to the at least one second server substantially on the determined unused bandwidth.
- 18A software product for replicating content data stored on a first server to at least one second server, said software product comprising:at least one machine readable medium;and programming code, carried by the at least one machine readable medium, for execution by at least one computer, wherein the programming code comprises: a congestion mechanism for determining unused bandwidth on a portion of a common link of an access data network, carrying subscriber traffic and over which the first server and the at least one second server communicate;and a first transmitting mechanism for causing transmission of content data stored on the first server to the at least one second server substantially on the determined unused bandwidth.
Independent claims2
171 paragraphs in 6 sections, as filed
CROSS-REFERENCE TO RELATED APPLICATION
0001This application is a continuation-in-part of application Ser. No. 09/635,695, entitled SUPPORT FOR QUALITY OF SERVICE AND VERTICAL SERVICES IN DIGITAL SUBSCRIBER LINE DOMAIN, filed Aug. 10, 2000.
FIELD OF THE INVENTION
0002Certain concepts involved in the present invention relate to techniques for implementing data communication services, for example in a local access network utilizing digital subscriber line technology, to support quality of service (QoS) and local introduction of vertical services. Other concepts involved in the present invention relate to distribution of content from a hub site to a server located at a central office through such a network.
BACKGROUND
0003Modern society continues to create exponentially increasing demands for digital information and the communication of such information between data devices. Local area networks use a network, cable or other media to link stations on the network for exchange of information in the form of packets of digital data. These networks have proven quite successful in providing data communications in commercial applications. However, the common local area network architectures require installation of specialized wiring and use of specific wiring topologies. For example, the most popular network protocols, such as Ethernet, require special rules for the wiring, for example with regard to quality of wire, range of transmission and termination. Furthermore, to extend communications to a wider domain still requires connection of at least one node of the local area network out to a wider area network, such as the network of an Internet Service Provider (ISP). High speed links enabling such wide area access from a LAN domain, for example using T1 lines, are quite expensive and justified only for hi-end commercial users.
0004A number of technologies are being developed and are in early stages of deployment, for providing substantially higher rates of data communication, for example ranging form 640 kb/s to 7.1 Mb/s. For example, cable television companies are now beginning to offer ‘cable modem’ services, which allow customers to communicate data over available bandwidth on the coaxial cable of a cable television network. After considering several other options, a number of the local telephone carriers are working on enhancements to their existing copper-wire loop networks, based on various xDSL technologies.
0005The term xDSL here is used as a generic term for a group of higher-rate digital subscriber line communication schemes capable of utilizing twisted pair wiring from an office or other terminal node of a telephone network to the subscriber premises. Examples under various stages of development include ADSL (Asymmetrical Digital Subscriber Line), HDSL (High data rate Digital Subscriber Line) and VDSL (Very high data rate Digital Subscriber Line).
0006The current design goals of DSL data networks for Internet access do not support high-end vertical services, that is to say services demanding IP-based applications that require assurance of some level of quality of service (QoS). For example, packet-switched Voice over IP (VoIP) requires low latency, low jitter (i.e., a relatively constant bit rate), and non-correlated packet loss. Streaming video has similar requirements, and in addition, requires high bandwidth. DSL data networks designed to support high speed Internet and Intranet access have been optimized to support traffic that is bursty and is not sensitive to latency or jitter. For example, current implementations supporting ATM cell traffic employ the Unspecified Bit Rate (UBR) class of service, which does not provide any bandwidth or delay guarantees. Consequently, transport of video materials through such DSL data networks inflicts video delays, loss of audio/video synchronization, and image fragmentation.
0007Furthermore, lengthy bandwidth intensive sessions for video or other broadband applications may degrade the throughput to all other subscribers served through a shared node, such as a gateway router or a concentrated link. For two-way video, upstream will have even worse quality and throughput problems, due to the best effort nature of the DSL data network implemented for Internet access and because the upstream bandwidth is significantly less than that of the downstream channel.
0008To appreciate the situation and problems, it may be helpful here to consider an ADSL data implementation of a local access network, as a representative example, in somewhat more detail. <figref idref="DRAWINGS">FIG. 8</figref> is a block diagram of a typical ADSL data network of the type currently in-use by a number of incumbent and competitive local exchange carriers to provide high-speed access to Internet Service Providers (ISPs) and thus to the Internet. <figref idref="DRAWINGS">FIG. 9</figref> provides an alternative functional illustration of the elements of such a network. Of particular note, <figref idref="DRAWINGS">FIG. 9</figref> shows the various protocol stacks in association with the appropriate network elements.
0009As shown in <figref idref="DRAWINGS">FIG. 8</figref>, a central office (CO) <b>100</b> provides plain old telephone service (POTS) and digital subscriber line data service for a number of customers. For purposes of discussion, assume that the equipment at each of the various customer premises <b>200</b> connects directly to the CO <b>100</b> via twisted pair type copper wiring <b>300</b>. In an actual implementation, many customers may connect through such wiring to a remote terminal linked to the CO via optical fiber.
0010At each customer premises <b>200</b> in our example, the copper loop <b>300</b> carrying both the POTS and ADSL signals connects through a Network Interface Device (NID) <b>201</b> placed at the side of the home. A two pair loop is installed from the NID to the location where the ADSL unit <b>203</b>, typically an ATU-R modem, is located in the home. One pair connects all of the signals on the line <b>300</b> from the NID <b>201</b> to the ADSL modem <b>203</b>. Within the ATU-R type modem <b>203</b>, a passive splitter/combiner type filter segregates the POTS signal and the data signals. The POTS signal is transmitted over the second twisted pair back to the NID <b>201</b>. The POTS line is then connected to the in-home wiring extensions at the NID <b>201</b>, for distribution to one or more standard telephone devices <b>205</b> in the home.
0011Within the ATU-R type ADSL modem <b>203</b>, the downstream coded ADSL signal is demodulated and decoded to an appropriate data interface protocol for connection to the PC <b>215</b>. The PC <b>215</b> or other data device (<figref idref="DRAWINGS">FIG. 9</figref>) also sends data to the ADSL modem <b>203</b>. The modem <b>203</b> modulates the upstream data and transmits appropriate signals over the line <b>300</b><sub>1 </sub>or <b>300</b><sub>2 </sub>to the corresponding modem <b>113</b><sub>1 </sub>or <b>113</b><sub>2 </sub>in the CO <b>100</b> (<figref idref="DRAWINGS">FIG. 8</figref>). The ATU-R interface may support bridging, such that multiple users can share the ADSL modem <b>203</b>, for two-way data communication through the CO <b>100</b>.
0012The lines <b>300</b> for the customer premises <b>200</b> connect through the main distribution frame (MDF) <b>101</b> to a Digital Subscriber Line Access Multiplexer (DSLAM) <b>111</b>. The DSLAM includes a bank of ADSL terminal units of the type intended for central office applications, identified as ATU-Cs <b>113</b>. The DSLAM also includes a multiplexer/demultiplexer (MUX) <b>115</b>.
0013Within the DSLAM <b>111</b>, each customer line <b>300</b> connects to an assigned ADSL terminal unit <b>113</b> in the central office (ATU-C). In the example illustrated, the first customer's line <b>300</b><sub>1 </sub>connects through the MDF <b>101</b> to a first ATU-C <b>113</b><sub>1 </sub>in the CO <b>100</b>. The second customer's line <b>3002</b> connects through the MDF <b>101</b> to a second ATU-C <b>113</b><sub>2 </sub>in the CO <b>100</b>. The ATU-C type ADSL units <b>113</b> include appropriate frequency dependent combiner/splitters, for segregating out the voice telephone traffic. Thus each ADSL unit <b>113</b> provides a connection for telephone traffic from the associated line <b>300</b> to the POTS switch <b>103</b>.
0014The ADSL units <b>113</b> in the CO (ATU-Cs) essentially act as modulator/demodulators (modems) for sending and receiving data over the subscriber telephone lines <b>300</b>. On the network side, each of the ATU-Cs <b>113</b> connects to the MUX <b>115</b>. The MUX <b>115</b> multiplexes and demultiplexes the upstream and downstream data for the ADSL modems <b>113</b> and provides a connection to a high-speed link <b>119</b>. Through subtending, the MUX <b>115</b> may also provide a data concentration for the communications over the link <b>119</b>.
0015In a typical implementation, the concentrated data communications utilize a DS-3 link <b>119</b>. However, because of increasing traffic demands, it is becoming necessary to upgrade the link <b>119</b> to SONET optical fiber, such as OC-3 or in some cases even OC-12. The link <b>119</b> provides two-way data communication between the central office <b>100</b> and a data hub <b>121</b>. In practice, this is a relatively long or wide area link using expensive interoffice facilities.
0016On the upstream side, the high-speed interoffice link <b>119</b> terminates on an ATM switch <b>123</b> for the ADSL data network (ADN). Although only one link <b>119</b> appears in the drawing, the asynchronous transfer mode (ATM) switch <b>123</b> will typically service a number of DSLAMs <b>111</b> in various end offices via similar DS or OC links. The ATM switch <b>123</b>, in turn, provides a high-speed connection to a gateway router <b>125</b> coupled to an ATM cell relay network <b>129</b>. Typically, the ATM switch <b>123</b> will aggregate traffic from a number of such links <b>119</b> onto an OC-3 or higher rate SONET link to the router <b>125</b>. The router <b>125</b> and the cell relay network <b>129</b> enable transport of ATM cells for the subscribers to and from equipment of one or more Internet Service Providers (ISPs), shown by way of example as a concentrator <b>131</b> coupled to the public packet switched network commonly known as the Internet <b>132</b>.
0017The illustrated local access type ADN network provides ATM cell transport from a customer premises <b>200</b> to the ISP concentrator <b>131</b>. The ATM cells serve as the layer-2 routing or switching protocol for the lowest level definition of connectivity between two points of the network. Higher level protocols ride within the ATM cells.
0018The ATU-Rs <b>203</b> and the customer premises data equipment <b>215</b> connect via an Ethernet coupler. The customers' equipment communicates across the ADSL data network utilizing Ethernet, and the wide area communication involves transport of Internet protocol information typically in TCP/IP frames within Ethernet frames. The Ethernet frames carrying the TCP/IP frames are adapted into ATM cells. Attention is directed to the protocol stacks illustrated in the lower half of <figref idref="DRAWINGS">FIG. 9</figref>.
0019To efficiently provide cell relay, each customer is assigned an ATM virtual circuit that extends from the ATU-R <b>203</b> in the respective customer premises <b>200</b> to the gateway router <b>125</b>. Although it was originally envisioned that ATM would support switched logical channels or virtual circuits, to date, such logical switching has proven impractical to implement and administer. Consequently, current practical ATM networks actually utilize permanent virtual circuits, not switched virtual circuits. For a given subscriber, the carrier therefore provisions an ATM permanent virtual circuit from the ATU-R <b>203</b> to the gateway router <b>125</b>. The carrier programs one or more nodes along the path of that logical circuit, particularly the DSLAM <b>111</b>, to regulate traffic on the virtual circuit to the upstream and downstream rates corresponding to the grade of service to which the particular customer subscribers. All data traffic for the subscriber goes over the entire length of the permanent virtual circuit, and most if not all nodes along that path limit that traffic to the rates of the subscription as defined in the provisioning data.
0020The virtual circuit may be thought of as a solid pipe. All traffic passes through the entire length of the pipe-like virtual circuit, regardless of how many switches or other nodes the circuit passes through. The layer-2 protocol defining the circuit carries all of the higher level traffic end-to-end. Higher layer protocols are visible only at the ends of the pipe. Hence, any traffic flow processing intended to utilize the higher layers must occur at some point past one end or the other end of the virtual circuit.
0021The gateway router <b>125</b> also terminates permanent virtual circuits through the cell relay network <b>129</b> going to/from the ISP concentrators <b>131</b>. The gateway router <b>125</b> aggregates traffic between a number of subscribers and each respective ISP. The ISP equipment <b>131</b> typically implements a variation of a point-to-point protocol (PPP) specifically adapted to ride over Ethernet, referred to as “PPP over Ethernet” (PPPoE). The virtual circuits to the ISPs, however, do not have sufficient capacity to simultaneously carry all subscriber traffic at the maximum rates of the customers' subscriptions. The MUX <b>115</b>, the ATM switch <b>123</b>, and the gateway router <b>125</b> concentrate and regulate the subscriber traffic going to and from the ISPs, typically on some type of “best efforts” basis.
0022In a typical Internet access service offering, the most expensive service tier provides 7.1 Mbps for downstream communication and 680 kbps for upstream communication. The next grade of service provides 1.6 Mbps for downstream communication and 90 kbps for upstream communication, whereas the lowest tier of service provides 640 kbps for downstream communication and 90 kbps for upstream communication. The maximum grade of service offered to an individual subscriber depends on the rates for which the subscriber's line can qualify, although the subscriber may opt for a lower rate service since the higher-rate service is more expensive.
0023The approach outlined above relative to <figref idref="DRAWINGS">FIGS. 8 and 9</figref> works well for Internet access if the traffic relates to web access, file transfers and the like, which do not require guaranteed quality of service. Various segments of the Internet industry, however, are rapidly developing new multimedia services and applications that already are pushing the capabilities of such a network. For example, increasingly, Internet traffic includes a number of types of communication that require a guaranteed quality of service. Voice telephone communication over IP is extremely sensitive to latency and jitter. The permanent virtual circuits provide an unspecified bit rate (UBR) service and do not guarantee any minimal amount of delay or jitter. Also, because the rates are set by subscription, the service tends to be relatively inflexible. Some services, such as multicasting of broadband information from the Internet into the local access ADN for a large number of concurrent users, can quickly overload one or more nodes or critical links of the network, for example the link <b>119</b> between the DSLAM <b>111</b> and the ATM switch <b>123</b> at the hub <b>121</b>.
0024Most industry experts propose to increase the services available via the public Internet. However, because the higher layer protocols are visible only on the Internet side of the virtual circuit “pipe,” these services all must be implemented out past the end of the virtual circuit, at least behind the gateway router <b>129</b> and most likely in the public network, where it is possible to view and route based on higher level protocols, particularly Internet protocol (IP). Such a migration strategy to implement new services creates severe problems. For example, in the network of <figref idref="DRAWINGS">FIG. 8</figref>, if a customer at premises <b>200</b><sub>1 </sub>desired to order a video on demand, the customer would communicate via the assigned permanent virtual circuit and the ISP to a server on the Internet <b>132</b>. The server would send the video stream back through the Internet <b>132</b>, the ISP equipment <b>131</b>, the cell relay network <b>129</b> and the virtual circuit from the router <b>125</b> to the ATU-R <b>203</b> for handoff to a PC or the like at <b>215</b>. If the rate of the requested video exceeds the customer's subscription rate, the customer could not view the video in real time during the download. Even if the rate of the requested video is below the customer's subscription rate, loading in the Internet or the local access network may impose delays and/or jitter in communication of some segments of the requested video. Assuming that the hub <b>121</b> and the links <b>119</b> implement a subscriber concentration, ordering of videos or similar broadband files from the Internet <b>132</b> quickly consumes the shared resources through the hub <b>121</b> and the links <b>119</b>, reducing the rates of service provided to other customers seeking concurrent Internet access.
0025It might be possible to increase the capacity of the links <b>119</b> and/or the hubs <b>121</b>; however, this tends to increase the carrier's recurring costs and often makes the overall service(s) of the ADN network economically impractical.
0026It has also been suggested to provide customers guaranteed quality of services for some portion of their communications, by segregating the traffic carried between the customer premises and the hub <b>121</b>. This would require assigning a plurality of ATM permanent virtual circuits to each subscriber, one for each different guaranteed level of quality of service and one for all other Internet traffic for the subscriber. Administration and provisioning of one virtual circuit per subscriber is already complicated, and the number of virtual circuits through any given ATM node is limited by current equipment designs. Expanding the number of permanent virtual circuits per subscriber to support multiple QoS tiers of service therefore would be quite expensive, and the management thereof would become a nightmare. To support an increased number of virtual circuits, many having guaranteed QoS requiring some substantial minimum rate at all times, would also require that the operator substantially upgrade the network to increase the end-to-end capacity all the way to the wide area network <b>132</b>.
0027Furthermore, to actually receive the desired QoS requires that all elements involved in the communication must guarantee the desired level or quality of service. For communications across the public Internet <b>132</b>, this means that various nodes and links on the public Internet must be available and capable of providing a guarantee of the desired QoS. In point of fact, few nodes on the public Internet actually support any type of QoS. Hence, even if the ADN supported a desired QoS, most subscribers would not benefit from that service because their communications over the public Internet would have no QoS guarantee, and would suffer from the usual problems of latency and jitter.
0028Consequently, current deployments of ADSL-based data networks, such as shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref> generate many customer complaints. From the customer perspective, the service does not deliver the data rates that the customer pays for on a consistent basis. The customer typically blames such problems on network equipment failure. In fact, most of the problems already are due to virtual circuit congestion problems, of the kinds outlined above. Essentially, the ADN network is crippled by the unpredictable nature of the service levels that the customers perceive due to congestion on the ADN and on the public Internet.
0029Also, with this approach, because all of the major service elements are implemented in servers accessible to the Internet, all of the services are subject to severe security risks. Each service provider's server is accessible to virtually any computer coupled for communication via the Internet. This openness is a desirable feature of the public Internet. However, a consequence is that any such server is accessible to and thus subject to attack from any hacker having Internet communications capabilities. Popular services, particularly those generating substantial revenues, become prime targets for attack.
0030Another area of problems is that the ADN does not offer the carrier any technique for offering its own differentiated service applications. To compete with other service providers, the carrier operating the ADSL-based data network needs to introduce its own multimedia services, for example, its own video services to compete with video services of cable television companies (that offer competing Internet access services). As noted above, however, introduction of a new service, such as true video on demand or broadcast video requires communications via the public Internet <b>132</b>. This is true even if the carrier operating the network of <figref idref="DRAWINGS">FIGS. 8 and 9</figref> wanted to initiate its own video service(s).
0031Hence, there is an ongoing need to improve the architecture and operation of a digital subscriber line data communication network, particularly to facilitate finer gradation of services within the local network. The need, first, is for such a local network to support introduction of services on a ‘vertical’ basis within the local access network separate and apart from the common forms of Internet traffic, both for commercial differentiation and for increased security.
0032As one type of vertical service, there is a further need for services implemented within the local access network for distribution of content to the customers, e.g. local video or music or multimedia, on-demand. Such vertical service insertion of locally stored content creates certain related needs. For example, this insertion would give rise to a further need, which is to transfer content from a central content server, within some hub site, to local content servers within the respective central offices. Further, this distribution of content must utilize some mechanism so that it will not compromise the quality of service for broader network traffic between the hub site and the respective central offices.
0033In a related need, the local network needs to support a number of different levels of quality of service (QoS). There also exists a need for upstream traffic to be shaped by customer equipment located at or near the interface between a customer's network and the ADN according to traffic destinations.
SUMMARY OF THE INVENTION
0034A general objective of the invention is to implement an enhanced digital communication network for subscriber lines that supports vertical introduction of new communication and/or multimedia services.
0035A further objective is to support multiple levels or grades of quality of service within the access network.
0036Another objective of the invention relates to improvement of the cost effectiveness of the data network, for example, by reducing the demand for high-capacity interoffice links while increasing the bandwidth available at the network edge for at least some types of services.
0037A related objective is to provide a technique for introduction of new high-end services near the network edge, such as content distribution, from a domain that is more secure and therefore less subject to hacker attacks.
0038A further objective of the invention is to distribute content between a central content server within a hub site and local content servers in the vertical services domains of the respective central offices. The distribution of content is accomplished utilizing bandwidth between the hub site and the respective vertical services domains that are unused by subscriber traffic.
0039The invention relates to methods and network architectures facilitating distribution of content between servers, in an access data network. Over a common network link, the distribution uses otherwise available capacity. Broader classes of traffic have a higher priority for accessing the bandwidth and are not impacted by the transport of content data over the common link. The distributed content then is available for delivery, for example on an “on-demand” basis to end-use customers.
0040The preferred embodiments of the ADN architecture alleviate many of the other noted problems by providing an intermediate node, typically an enhanced switch, to segregate upstream traffic based on analysis of the type of communication. This analysis utilizes protocol information contained in each communication, for a protocol higher than the switching protocol, that is to say higher than a protocol used to define the customer's logical circuit. One type of traffic remains on the virtual circuit, whereas other traffic is handed off to a vertical services domain. The node also provides a point to aggregate traffic from the vertical services domain with other traffic on the subscriber's logical circuit, for transport to the customer premises equipment.
0041The switch at the intermediate node essentially subdivides the upstream traffic and aggregates downstream traffic, associated with each subscriber line. One branch goes to a gateway router and hence to one or more ISP(s) at the rate corresponding to the Internet access subscription. It may be helpful to consider this as long distance or wide area traffic for the subscriber. The other branch is for local traffic, to and from the locally connected vertical services domain. The remote content delivery servers are coupled to various vertical services domains, typically in different end offices. The interconnection to the vertical services domain supports QoS and introduction of vertical services not easily provided from the public Internet, such as video on demand, multicasting, and voice over IP. The vertical services domain is relatively secure since it is not accessible from the public Internet.
0042The vertical services domain also represents a communication network. The vertical services domain, however, preferably takes the form of a data network optimized for local transport of vertically injected services, that is to say local data traffic. In view of its local nature, it is easier and more cost effective to provide high bandwidth services, such as content distribution to customers, from the local domain. The vertical services network, for example, could take the form of a giga-bit Ethernet type local area network. Also, it is easier to adapt the vertical services network to support service level agreements with customers with regard to quality of service. In many cases, it actually is sufficient to support QoS on the one hop through the ATM switch, itself.
0043An aspect of the invention relates to the distribution of content from a central content server within a hub site to local content servers within the respective vertical services domains of remote central offices. Content is routinely and periodically distributed between a plurality of local vertical services domains and the hub site server. The hub site may include a gateway router, which is an ATM switch, and the central content server in communication with the gateway router. Alternatively, the hub site may include an enhanced hub switch and one or more further local services domains. In such an implementation the central content server communicates via the local services domain and the hub switch.
0044Each of the remote central offices may house another switch, with vertical services insertion capabilities, and local content servers in communication with the vertical services insertion switch. The content is distributed, such that the distribution of content does not interfere with subscriber traffic between the hub site and the respective switches at the respective central offices. This is accomplished by utilization of otherwise unused bandwidth between the hub site and remote central offices during time periods when subscriber traffic does not utilize the entirety of this bandwidth. Once the content is distributed and stored on the local content servers at the remote central offices, the end users served by each central office can access content at a high speed from the nearest vertical services domain, without compromising the bandwidth allocated for Internet traffic or other traffic between the hub site and the respective remote central office.
0045A further aspect of the invention relates to unique software for implementing the distribution of content. A software product, in accord with this aspect, includes at least one machine readable medium and programming code, carried by that medium. Although the inventive concepts encompass operation from a single, common server, in a preferred embodiment, the code includes several cooperating applications which may reside in separate media and run on two or more servers or other network nodes.
0046A computer readable medium, as used herein, may be any physical element or carrier wave, which can bear instructions or code for performing a sequence of steps in a machine readable form. Examples of physical forms of such media include floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic medium, a CD-ROM, any other optical medium, a RAM, a ROM, a PROM, an EPROM, a FLASH-EPROM, any other memory chip or cartridge, as well as media bearing the software in a scannable format. A carrier wave type of medium is any type of signal that may carry digital information representative of the instructions or code for performing the sequence of steps. Such a carrier wave may be received via a wireline or fiber-optic network, via a modem, or as a radio-frequency or infrared signal, or any other type of signal which a computer or the like may receive and decode.
0047To support the QoS requirements, a feature of the preferred embodiments involves certain queuing and tagging operations within the switch at the intermediate node. Essentially, the switch will maintain two or more queues for each permanent virtual circuit. The switch distinguishes the queues based on importance. As the switch receives cell transmissions for transport over the virtual circuit, for example to the customer premises or between servers, the switch will internally tag each cell as to its importance level and place the cell in the appropriate queue. The switch may implement any one of a number of different algorithms to select and transmit cells from the various queues. For subscriber services, for example, the particular algorithm is selected to implement QoS in conformance with the subscriber's service level agreement with the carrier and/or agreements between the carrier and the vertical services providers.
0048In preferred embodiments, the same QoS mechanisms are applied to the logical circuit(s) carrying content between the servers. Using these mechanisms, it is possible to provision such a circuit with a combination of a small guaranteed rate and an “as-available” capacity, such as unspecified or available bit rate service. Alternative embodiments use one or more ATM PVC circuits, for each logical link between the servers. If one PVC is used, for example, the ATM circuit may be provisional with UBR+ service, to have a minimal reserved bandwidth in combination with an unspecified bit rate (UBR) service.
0049Within the one virtual circuit assigned to the individual subscriber, the invention actually provides multiple tiers of service, preferably with multiple levels of QoS. Also, at different sections along the virtual circuit “pipe,” the network provides different levels of rate shaping. All layers and all services are available at the home, but different services receive different treatments in the network conforming to the different levels of QoS. The inventive approach, however, does not require each subscriber to have multiple virtual circuits.
0050Services provided on the vertical services domain appear as IP data services. Virtually any communication service may utilize the vertical services network and through it to gain access to the carrier's local customer base, simply by providing an IP interface for coupling to the vertical services network. For example, it is a simple matter to connect any digital source of broadcast audio or video information, such as a direct satellite broadcast receiver system similar to those used today in residential applications, through an IP interface. Such a broadcast source and interface can provide the full range of received video services, over the vertical services network. The access data network may distribute the video programming to a number of access switches within a local geographic area. The switch provides an optimum point for frame or cell replication for multicasting services. Hence, in our video example, the switch replicates and distributes frames for the broadcast service over the digital subscriber line circuits to customers desiring to view the programming.
0051Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
0052The drawing figures depict preferred embodiments of the present invention by way of example, not by way of limitations. In the figures, like reference numerals refer to the same or similar elements.
0053<figref idref="DRAWINGS">FIG. 1</figref> is a functional block diagram of a digital subscriber line data network supporting enhanced services in accord with the inventive concepts.
0054<figref idref="DRAWINGS">FIG. 2</figref> is a slightly modified functional block diagram of network of <figref idref="DRAWINGS">FIG. 1</figref>, illustrating the protocol stacks used in the various network elements.
0055<figref idref="DRAWINGS">FIG. 3</figref> is a functional block diagram of the network showing the service level agreements (SLAs) for which the network provides appropriate QoS.
0056<figref idref="DRAWINGS">FIG. 4A</figref> is a logical diagram of the functional elements of an L3/4 switch, for use in the inventive network of <figref idref="DRAWINGS">FIGS. 1-3</figref>.
0057<figref idref="DRAWINGS">FIG. 4B</figref> is a functional block diagram of a digital subscriber line data network with a central content server proximate to the hub site and a local content server in the vertical services domain, proximate to the central office.
0058<figref idref="DRAWINGS">FIG. 4C</figref> is a bandwidth utilization graph illustrating content distribution over bandwidth unused by subscriber traffic, in accord with the invention.
0059<figref idref="DRAWINGS">FIG. 5</figref> is a block diagram of a modified portion of the network, useful in explaining migration to other types of physical transport and switching/routing protocols.
0060<figref idref="DRAWINGS">FIG. 6</figref> is a block diagram of a portion of the network of <figref idref="DRAWINGS">FIG. 5</figref>, showing the interconnection thereof with the wide area network and the local vertical services domain.
0061<figref idref="DRAWINGS">FIG. 7</figref> is a block diagram of a modified embodiment of the network, useful in explaining certain preferred aspects of the content distribution in accord with the invention.
0062<figref idref="DRAWINGS">FIG. 8</figref> is a block diagram of a prior art asymmetrical digital subscriber line data network.
0063<figref idref="DRAWINGS">FIG. 9</figref> is a slightly modified functional block diagram of the prior art network illustrating the protocol stacks used in the various network elements.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
0064The inventive network architecture introduces QoS into the ADN, in a manner that enables the delivery of sophisticated and demanding IP-based services to subscribers. The architecture does not affect existing Internet tiers of service such that the promised rates for such access appear the same as offered today. Also, the new architecture is cost-effective in terms of initial costs, build-out, and ongoing operations. The architecture utilizes an access switch or router capable of examining and selectively forwarding packets based on a relatively higher layers of the protocol stack, that is to say based on information encapsulated within the layer-2 information utilized as the lowest level definition of connectivity through the network. The access switch enables segregation of upstream traffic by communication type and downstream aggregation of wide area traffic together with traffic from a local vertical services domain.
0065In the downstream direction, the switch aggregates traffic for each subscriber. The switch receives the rate-limited traffic from the packet switched network, on the subscriber's logical circuit. The switch also receives any downstream traffic intended for the subscriber, from the vertical services network. The switch combines this traffic and sends the combined communications downstream over the subscriber's logical circuit to the customer premises, at the optimum downstream rate that the subscriber's facilities can support.
0066The upstream segregation and the downstream aggregation allow insertion of new localized services on a “vertical” basis, at the intermediate node. The invention encompasses vertical insertion of a wide range of services from the new vertical domain. One class of services, of particular interest here, relates to content distribution from servers in the vertical domain, e.g. on-demand. To support such services, the network should also allow efficient distribution of content between a central or “hub” site and the servers in the local vertical services domains.
0067In accord with the invention, content data stored on a central content server at a hub site is systematically and periodically replicated and updated to and from local content servers in the vertical services domains at the respective central offices. Accordingly, a customer serviced by a central office has access to the content stored on the local content servers at a relatively high data rate that does not substantially compromise the rate to which the customers access a broader network, such as the Internet. Data replicated from the central content server to the respective local content servers can be conveniently communicated over the link between the hub site and central offices, which also carries the customers' broader network traffic. The present invention mitigates the problem of network congestion during replication of data between the central content server and the respective local content servers, by only transferring such content data using bandwidth that is not used by the broader class(es) of network traffic. This aspect of the invention requires continuous analysis of the bandwidth utilizational of the link between the hub site and the respective central offices.
0068<figref idref="DRAWINGS">FIG. 1</figref> provides a high-level functional illustration of an exemplary digital subscriber line network, specifically an ADSL data network <b>10</b>, implementing the various concepts of the present invention. <figref idref="DRAWINGS">FIG. 2</figref> provides an alternative functional illustration of the elements of such a network. Of particular note, <figref idref="DRAWINGS">FIG. 2</figref> shows the various protocol stacks associated with the appropriate network elements that utilize those stacks. The end-user may be a single PC user or a small business or a residential LAN user. The data equipment of such users typically includes servers and PCs and may include a variety of other devices, such as fax machines, televisions, recorders and remote controlled appliances, having data communication capabilities.
0069The customer access link comprises an XDSL twisted pair, although those skilled in the art will recognize that the invention is readily adaptable to networks using other types of links to the subscriber premises. In the illustrated embodiment, the network <b>10</b> supports ADSL, which the carrier may offer in grades supporting 640 kbps, 1.6 Mbps or 7.1 Mbps (downstream) rates for Internet access. The actual communications over the DSL loops, however, run adaptively at the maximum rates that the line conditions allow.
0070The illustrated first embodiment of the ADSL-based local access data network or “ADN” <b>10</b> provides access to two different network domains for communication services. The two network domains are logically separate. In most implementations, the first domain may be considered as a long distance or wide area domain, whereas the second domain is a local network domain. In the illustrated example, the ADN <b>10</b> provides access to a first domain in the form of a wide area internetwork, such as the public Internet, corporate local area networks (LANs), and the like, represented by the network cloud <b>11</b> for the ISPs. The high speeds available through the local network <b>10</b> enable a wide range of communications, for example, of text data, of video data, for multimedia, for web browsing, of transfers of files, for database searching, and the like via the network(s) <b>11</b>.
0071The inventive ADSL-based local access network <b>10</b> also offers access to a wide variety of other IP-based services through a local data network <b>13</b> serving as the vertical services domain (VSD). The vertical services typically are high-end services requiring certain QoS levels and often having a certain local characteristic. Many of these services entail distribution of content, from local storage servers in the vertical services domain to actual customers. Examples of the vertical services, including content distribution services, are discussed in more detail later. The vertical services network offers an efficient domain from which the carrier can locally inject high-end services and/or services of other local providers. Because the vertical services domain is separate from the public Internet, equipment providing the vertical services is not subject to attacks directly from the public Internet.
0072The invention in this case particularly involves content distribution between a hub site and the servers in various vertical services domains. However, to appreciate the operation and advantages of that aspect of the invention, it may be helpful first to consider the overall network operation and the details of the vertical services insertion.
0073As shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, a central office (CO) <b>15</b> comprises one or more DSLAMs <b>17</b> and L3/4 ATM switch <b>19</b>. Elements of the CO <b>15</b> providing plain old telephone service (POTS) have been omitted for simplicity of illustration, since they are generally similar to those shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref>.
0074The switch <b>19</b> is designated as an “L3/4” switch here as a matter of convenience, to illustrate that the switch <b>19</b> has the capability to make selective packet forwarding decisions based on protocol information at some level that is above the L2 level that the switch normally utilizes to define or establish logical circuit connectivity. It will be recognized, however, that some of the protocols, although higher than the ATM type level 2 protocol used by the preferred switch are themselves often thought of as level 2 protocols even though they are above or encapsulated in the ATM type level 2 information. Also, decisions as to the selective forwarding may be made in response to monitoring of any level of the protocol stack above the L2 level that the switch normally utilizes to define or establish logical circuit connectivity, for example from any level above ATM all the way up to the L7 application layer.
0075Returning to the discussion of <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, for purposes of this discussion, assume that the equipment at the various customer premises connect directly to the CO <b>15</b> via twisted pair type copper wiring <b>21</b>. In an actual implementation, many customers may connect through such wiring to a remote terminal linked to the CO <b>15</b> via optical fiber. Other hardwired, optical or wireless implementations of the digital subscriber lines are discussed later. In the illustrated embodiment, each line <b>21</b> from a customer premises connects to an ATU-C within one of the DSLAMs <b>17</b>.
0076On the customer premises side, the digital subscriber line circuit <b>21</b> connects to an ADSL terminal unit (remote) or ATU-R <b>23</b>. The ATU-R <b>23</b> is a modulator/demodulator (modem) for communicating over a twisted wire pair type line <b>21</b>, in accord with the ADSL protocols. The ATU-R in turn connects to customer premises equipment, shown by way of example as a PC <b>25</b> at each location (<figref idref="DRAWINGS">FIGS. 1 and 2</figref>). Those skilled in the art will recognize that the customer premises equipment <b>25</b> may include a wide range of other types of devices having data communications capabilities (see e.g., <figref idref="DRAWINGS">FIG. 3</figref>).
0077The ADSL user's normal telephone equipment (not shown) also connects to the line <b>21</b>, either directly or through a frequency combiner/splitter, which often is incorporated in the ATU-R. The normal telephone signals are split off at both ends of the line and processed in the normal manner.
0078For digital data communication purposes, the ATU-C and ATU-R modem units create at least two logical channels in the frequency spectrum above that used for the normal telephone traffic. One of these channels is a medium speed duplex channel; the other is a high-speed downstream only channel. Such modems may implement either one of two techniques for dividing the usable bandwidth of the telephone line to provide these channels. One approach is to divide the usable bandwidth of a twisted wire pair telephone line by frequency, that is to say by Frequency Division Multiplexing (FDM). The other approach uses Echo Cancellation. FDM uses one frequency band for upstream data and another frequency band for downstream data. The downstream path is then divided by time division multiplexing signals into one or more high-speed channels and one or more low speed channels. The upstream path also may be time-division multiplexed into corresponding low speed channels. With echo Cancellation, the upstream band and downstream band substantially over-lap. The modems separate the upstream and downstream signals by means of local echo cancellors, in a manner similar to that used in V.32 and V.34 modems.
0079The DSL modems may use a number of different modulation techniques to physically transport digital data streams. A number of implementations of the modems have used carrierless amplitude phase (CAP) modulation. Most current xDSL modems, however, utilize a discrete multi-tone (DMT) approach.
0080Returning to the discussion of the CO <b>11</b>, the structure and operation of each DSLAM <b>17</b> is essentially the same as those of the DSLAM <b>111</b> in the embodiment of <figref idref="DRAWINGS">FIG. 8</figref>, except that the control functionality of the DSLAM <b>17</b> is somewhat different. The DSLAM <b>17</b> controls the ATU-Cs to implement a rate-adaptive ADSL service, to adapt operations so as to maximize data rates for the communications over the individual subscriber lines. Essentially, the ATU-Cs and ATU-Rs signal each other over the lines to synchronize their modes of operation at parameter settings, which achieve optimum data throughput. Also, the DSLAM <b>17</b> does not need to monitor or limit the line rates, but instead relies on the rate-adaptive control algorithm to maximize the rates achieved over the ADSL circuits or provide rate-shaping for the ATM virtual circuits. Other network elements limit rates, where necessary.
0081The L3/4 ATM switch <b>19</b> is co-located with the DSLAMs <b>17</b>, within one central office <b>15</b>. As a result, it is practical to connect the multiplexer within each of the DSLAMs <b>17</b> over a high-speed data link directly to an appropriate port of the ATM switch <b>19</b>. Because these links are short, there is little or no cost imposed when implementing such links using wideband equipment. By itself, the co-location of the L3/4 ATM switch <b>19</b> with the DSLAM(s) <b>17</b> does not increase bandwidth. Rather, it makes increased bandwidth at the network edge economically feasible, due to proximity. Co-location removes the requirement to purchase expensive wide area transport (the SONET ring) to increase bandwidth. In particular, the direct OC3/OC12 connections between the DSLAM <b>17</b> and the L3/4 ATM switch <b>19</b> do not incur any recurring tariff expenses.
0082The ATM switch <b>19</b> connects through a SONET ring <b>27</b> to a gateway router <b>29</b> providing ATM transport through a cell relay network <b>30</b> (<figref idref="DRAWINGS">FIG. 2</figref>) to the ISPs shown at network <b>11</b> in the drawings. Most of the ISPs will utilize a concentrator or other equipment as their point of presence for Internet access (<figref idref="DRAWINGS">FIG. 2</figref>). In the preferred embodiment, the equipment <b>31</b> provides a point-to-point protocol (PPP) interface designed for transport over Ethernet (PPPoE). The ATM switch <b>19</b> also provides a connection to the local implementation of the VSD network <b>13</b>, for example via a giga-bit Ethernet port to a switch or other local network elements <b>18</b>.
0083The illustrated local access type ADN network <b>10</b> provides ATM cell transport from the customer premises to the ISP network(s) <b>11</b>. The ATM cells serve as the layer-2 protocol for defining contiguous switched connectivity. Higher level routing protocols, such as Ethernet and TCP/IP frames, ride within the ATM cells. Services of different types utilize different protocols at one or more layers above the ATM cell layer. In the preferred embodiments, all communications utilize Ethernet. However, communications to and from the ISPs use the noted PPPoE type Ethernet protocol. In contrast, communications to and from the vertical services domain use one or more of the other Ethertype protocols.
0084To efficiently provide cell relay, each customer is assigned a virtual circuit that extends from the ATU-R <b>23</b> in the respective customer premises to the gateway router <b>29</b>. This logical circuit is defined at the layer-2 protocol level. The presently preferred embodiments implement this logical communication circuit as an ATM permanent virtual circuit, although the inventive concepts may apply to other types of logical circuits or channels.
0085The gateway router <b>29</b> is the communication node of the access network <b>10</b> providing access to the wide area IP packet networks, of corporations or more often of Internet Service providers. The gateway router <b>29</b> terminates permanent virtual circuits through the cell relay network <b>30</b>, from the equipment <b>31</b> of each such wide area packet network provider <b>11</b>. The gateway router <b>29</b> also terminates the permanent virtual circuits from the subscribers through the data network <b>10</b>. For communication with a selected ISP network <b>11</b>, for example, the gateway router <b>29</b> routes cells from the permanent virtual circuit from the subscriber through to the permanent virtual circuit of the selected ISP network <b>11</b>. In the opposite direction, the gateway router <b>29</b> routes cells from the permanent virtual circuit from the selected ISP network <b>11</b> through to the permanent virtual circuit of the particular subscriber.
0086For the leg of the subscriber's logical circuit, extending from the L3/4 ATM switch <b>19</b> through the gateway router <b>29</b>, the carrier programs one or more nodes along the path behind the DSLAMs <b>17</b>, to regulate traffic on the virtual circuit to the rate corresponding to the grade of Internet access service to which the particular customer subscribes. In the preferred embodiment, at least one such node performing this rate shaping function is the L3/4 ATM switch <b>19</b>. All traffic going to and from the ISP network(s) <b>11</b> therefore is still limited to the rates defined in the service level agreement (SLA) for Internet access that the carrier has with the particular customer.
0087The portion of the virtual circuit extending between the ATM switch <b>19</b> and the ATU-R <b>23</b>, however, is not rate limited but instead runs at the maximum rate that the line will support using the rate-adaptive ADSL modem operation. In most cases, the rate-adaptive ADSL modem operation will support rates substantially higher than the subscription rate for Internet access service.
0088The L3/4 ATM switch <b>19</b> also provides the interconnection to the subscriber's virtual circuit for insertion of downstream traffic from the vertical services domain <b>13</b> and separation of upstream traffic from the subscriber's virtual circuit going to the vertical services domain <b>13</b>. In the preferred embodiments, decisions as to whether upstream traffic is destined for the vertical services domain <b>13</b> or should remain on the subscriber's virtual circuit going through the gateway router <b>29</b> and the cell relay network <b>30</b> to the ISPs <b>11</b> are based on an analysis of traffic type. The traffic type analysis relies on protocol information contained in the communications, which relates to layers of the protocol stack that are higher than the layer-2 switching protocol, in this case above the ATM layer.
0089As shown in <figref idref="DRAWINGS">FIG. 2</figref>, traffic destined for an ISP <b>11</b> utilizes a variation of a point to point protocol (PPP) intended to run on top of Ethernet, referred to as PPP over Ethernet or “PPPoE.” A ‘type’ indicator contained within the Ethernet frames identifies the PPPoE protocol. In contrast, traffic going to and from the vertical services domain utilizes other ‘types’ of Ethernet protocol. All traffic to and from the customer premises uses Ethernet frames carried within ATM cells.
0090The switch <b>19</b> therefore routes a subscriber's traffic going to and from an ISP <b>11</b>, upon detection of the PPPoE indicator in the level 3 data contained within the Ethernet cells. This traffic will also utilize public IP addressing. In contrast, the ATM switch <b>19</b> routes a subscriber's traffic going to and from the vertical services domain, upon detection of any other type of Ethernet protocol at level 3 or above in the protocol stack. The IP addressing in the vertical services domain <b>13</b> utilizes private-IP addresses, for example, as administered with a DHCP server (not shown) coupled to the network cloud <b>33</b>. Although shown separately, the cloud <b>33</b> may be implemented as a portion of the network providing the physical elements of the vertical services domain. The portion <b>33</b>, however, would typically be a logically separate domain that the carrier controls and restricts for its own network administration use.
0091<figref idref="DRAWINGS">FIG. 3</figref> depicts the logical division of the subscriber's traffic, as implemented at the ATM switch <b>19</b> in accord with the invention. As shown, the network <b>10</b> provides a logical “pipe” or circuit <b>35</b> extending to the networks <b>11</b> of one or more of the ISPs, for an Internet access application. The ATM switch <b>19</b> (<figref idref="DRAWINGS">FIG. 1</figref>) preferably performs a rate shaping or control function. The leg <b>35</b> of the subscriber's traffic extending to the ISP <b>11</b> provides upstream and downstream communication rates conforming to a service level agreement (SLA) applicable to the subscriber's Internet access application. As such, the communications over the subscriber's logical circuit, extending from the switch to the ISP, provide a first level of QoS. To the subscriber, service over the leg <b>35</b> appears the same as a subscriber selected grade of Internet access service as provided by older ADN architectures. <figref idref="DRAWINGS">FIG. 3</figref> illustrates chat rooms, web surfing and e-mail as examples of services an ISP might offer through the Internet Application SLA circuit <b>35</b> and the attendant portion of the subscriber's assigned logical circuit through the access network.
0092The network <b>10</b> also supports communications over one or more logical application paths <b>36</b> to local applications <b>37</b> hosted in the vertical services domain. Assuming that a subscriber with various equipment <b>25</b> also subscribes or otherwise participates in one or more of the vertical services, the local carrier (e.g. Verizon Communications in <figref idref="DRAWINGS">FIG. 3</figref>) offers a corresponding number of additional application SLAs with the customer. Each SLA for a vertical service may specify QoS parameters for the particular application, such as rate/bandwidth, latency, jitter, packet loss, packet sequence, security and/or availability. Examples of such applications hosted in the carrier's vertical services domain <b>37</b> include the illustrated voice over IP service shown as a V/IP gateway, as well as video services and some caching for high volume local web services. Communications for such applications utilize the one or more paths <b>36</b>. The present invention also supports segregation and aggregation of traffic for three or more domains, based on the higher-level traffic type analysis.
0093A feature of the switch, in accord with the invention, is that it prioritizes traffic for each customer to support QoS for the various services as required by service level agreements (SLAs) between the customer and the carrier. In this regard, one implementation of the L3/4 ATM switch <b>19</b> performs queuing and tagging operations in accord with the desired prioritization. The switch will maintain two or more queues for each subscriber's permanent virtual circuit. The switch distinguishes the queues based on importance or priority. As the switch receives cell transmissions for transport over the virtual circuit to the customer premises, the switch will internally tag each cell as to its importance level and place each cell in the appropriate queue based on the tag.
0094The tagging and prioritization may be based on traffic type or ‘Type of Service’ (ToS). Table 1 illustrates one example of the possible ToS levels that may be assigned to different communications. <tables id="TABLE-US-00001" num="1"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="5"><colspec colname="1" colwidth="42PT" align="left" /><colspec colname="2" colwidth="21PT" align="center" /><colspec colname="3" colwidth="35PT" align="left" /><colspec colname="4" colwidth="63PT" align="left" /><colspec colname="5" colwidth="56PT" align="left" /><thead><row><entry namest="1" nameend="5" align="center">TABLE 1</entry></row><row><entry /></row><row><entry namest="1" nameend="5" align="center" rowsep="1" /></row><row><entry /><entry /><entry /><entry /><entry>Internal</entry></row><row><entry /><entry /><entry /><entry>Customer</entry><entry>BA Mgmt</entry></row><row><entry /><entry /><entry /><entry>Traffic</entry><entry>Traffic</entry></row><row><entry>Relative</entry><entry>ToS</entry><entry>AR</entry><entry>Encapsulated</entry><entry>Rewritten</entry></row><row><entry>Priority</entry><entry>Value</entry><entry>Queuing</entry><entry>TOS</entry><entry>TOS</entry></row><row><entry namest="1" nameend="5" align="center" rowsep="1" /></row></thead><tbody valign="top"><row><entry>Critical</entry><entry>0</entry><entry>WFQ</entry><entry /><entry>OSPF, SNMP,</entry></row><row><entry>Management</entry><entry /><entry>(Control</entry><entry /><entry>ICMP, BGP</entry></row><row><entry /><entry /><entry>25%)</entry></row><row><entry>Future</entry><entry>1</entry></row><row><entry>Real Time</entry><entry>2</entry><entry>WFQ</entry><entry>Port numbers</entry></row><row><entry>Interactive</entry><entry /><entry>(High</entry><entry>identified</entry></row><row><entry /><entry /><entry>40%)</entry></row><row><entry>IP</entry><entry>3</entry><entry>WFQ</entry><entry>ICMP, IGMP, EGP,</entry><entry>IGMP, RADIUS</entry></row><row><entry>Application</entry><entry /><entry>(Medium</entry><entry>DNS, H.323 signal-</entry></row><row><entry>Control</entry><entry /><entry>30%)</entry><entry>ing, BGP, SIP,</entry></row><row><entry /><entry /><entry /><entry>Microsoft Media</entry></row><row><entry /><entry /><entry /><entry>Player Streaming</entry></row><row><entry /><entry /><entry /><entry>Media Control,</entry></row><row><entry /><entry /><entry /><entry>RTSP</entry></row><row><entry>One Way</entry><entry>4</entry><entry /><entry>UDP</entry></row><row><entry>Streaming</entry><entry /><entry /><entry>(ports 1024+)</entry></row><row><entry>Media</entry></row><row><entry>One Way</entry><entry>5</entry><entry /><entry>HTTP, HTTPS,</entry></row><row><entry>Batch</entry><entry /><entry /><entry>SNMP, Telnet</entry></row><row><entry>Unknown</entry><entry>6</entry><entry>WFQ</entry><entry>Other</entry><entry>Other</entry></row><row><entry /><entry /><entry>(Low</entry></row><row><entry /><entry /><entry>5%)</entry></row><row><entry>Non time</entry><entry>7</entry><entry /><entry>FTP, TFTP,</entry></row><row><entry>sensitive</entry><entry /><entry /><entry>SMTP</entry></row><row><entry namest="1" nameend="5" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>
0095The access switch <b>19</b> will examine the content of each communication and determine an appropriate ToS level, for example in accord with the table above. Based on the ToS level, the switch will add a tag to the cell(s) as part of its internal processing. Using the ToS tags, the switch will place each of the cells for a given subscriber into a corresponding one of a plurality of queues that the switch maintains for the subscriber's traffic.
0096The switch may implement any one of a number of different queue servicing algorithms to select and transmit cells from the various queues. For example, the switch <b>19</b> may implement one of several statistical algorithms, equal queuing, weighted queuing, priority selection from queues, etc. The particular algorithm is selected to implement QoS in conformance with the subscriber's service level agreements (SLAs) with the carrier. In most cases, particularly for service applications from the vertical services domain, the switch <b>19</b> will not normally drop any cells or packets. In the rare event that the switch <b>19</b> becomes congested, any dropping of cells is based on the priority level assigned to the frame, i.e., lowest priority first. Also, if the switch ever drops cells, it drops all cells for an effected lowest priority frame from the relevant queue.
0097The ability to prioritize traffic across the vertically inserted streams and the wide area (typically Internet) stream enables the operator to control flows through the ADN <b>10</b> so that the local access facility is not overwhelmed with content which exceeds its physical (rate adaptive) limitations. For example, the queuing rules preferably ensure that the ‘proper’ applications (based on insertion device based rules) obtain access to the limited rate adaptive bandwidth available on any given subscriber's line. Also, the insertion point, switch <b>19</b>, will usually sit behind the media conversion point (e.g., the DSLAM <b>17</b>). An OC3 or other facility between the switch <b>19</b> and the DSLAM <b>17</b> also could become congested. Preferably, the switch <b>19</b> or other element at the insertion point queues the traffic in such a manner that no downstream facility (OC3) limitations (which are independent of the rate adaptive DSL loop limitations) will result in packets being dropped.
0098The queuing will be done based on customer and network provider determined rules so that contention for the facilities facing the subscriber will be addressed via the dropping of the appropriate packets. That way an inserted video stream doesn't overwhelm an Internet or Voice stream (due to facility limitations). Among others, appropriate industry understood methods for accomplishing this queuing control include Weighted Fair Queuing (WFQ), Priority (PQ) Queuing, and Weighted Random Early Discard (WRED).
0099Also, the ability of the switch <b>19</b> to examine higher level information provides other advantages in network operations. For example, the switch can implement sophisticated filters on the higher level information, e.g., to provide security. As another example, the switch preferably performs measuring and monitoring to determine what if any packets are dropped (based on the physical rate adaptive limitations), and generates appropriate reports to an external operations system (not shown).
0100The introduction of the L3/4 ATM switch <b>19</b> in proximity to the DSLAM(s) <b>17</b> also provides benefits in terms of operation of the gateway router <b>29</b>. Due to the end-to-end use of the Unspecified Bit Rate (UBR) PVCs, the gateway router interface to the cell relay network <b>30</b> has been engineered to support a maximum of 2000-4000 PVCs (end users). This is essentially an over-provisioning of bandwidth that probabilistically avoids service degradation that could result from simultaneous demand for bandwidth. The ability of the L3/4 ATM switch <b>19</b> to perform QoS and rate shaping essentially reduces or ever removes this concern, because it significantly reduces the risk that the gateway router <b>29</b> will become a bottleneck. As a result, the ADN <b>10</b> can increase bandwidth efficiencies for this interface. Further, the capacity through the gateway router <b>29</b> need not be upgraded as often to support demand for increased bandwidth associated with new bandwidth-intensive services, since many such services are now introduced through the vertical services domain <b>13</b> and the L3/4 ATM switch <b>19</b>.
0101To fully understand an exemplary implementation of the various inventive concepts, it may be helpful to consider an ATM-based embodiment of the L3/4 switch <b>19</b>. <figref idref="DRAWINGS">FIG. 4A</figref> is a block diagram of the elements and functions of such a preferred embodiment of the switch <b>19</b>.
0102The preferred embodiments utilize Ethernet framing. As shown in the drawing, the switch <b>19</b> includes an Ethernet interface <b>41</b>, an ATM interface <b>42</b> and an associated physical interface <b>43</b> facing toward the subscribers. In an embodiment for use in the network of <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, the physical interface might take the form of one or more OC-3 or OC-12 links to the DSLAMs <b>17</b>. These links carry all ATM cell traffic going to and from the DSLAMs and hence to and from the customer equipment served through the particular switch <b>19</b>.
0103The switch <b>19</b> also includes an Ethernet interface <b>44</b>, an ATM interface <b>45</b> and associated physical interface <b>46</b> facing toward the gateway router <b>29</b> and hence the ISPs <b>11</b>. The physical interface <b>46</b> might take the form of one or more OC-12 or OC-48 links to the gateway router <b>29</b>. These links carry all ATM cell traffic going to and from the ISPs or other wide area inter-networks <b>11</b>. For these communications, the Ethernet interface <b>44</b> passes through PPPoE traffic, as specified by the Ethertype indicator in the cells transporting the relevant frame segments.
0104Facing the vertical services domain, the switch <b>19</b> includes an Ethernet interface <b>47</b> and a physical interface <b>48</b>. These interfaces conform to the particular network utilized by the carrier for the vertical services domain, such as giga-bit Ethernet over wire or optical links.
0105The switch fabric <b>49</b> performs the physical switching of data along various paths through the switch <b>19</b>, in response to instructions from a programmed routing controller <b>50</b>. <figref idref="DRAWINGS">FIG. 4A</figref> also shows the communications flow through the switch, for each subscriber. The switch <b>19</b> also implements a Decision Point <b>51</b>, shown for example within the Ethernet interface processing <b>41</b> on the subscriber facing side. At that point, the PPPoE traffic is separated from all other traffic. From that point, the PPPoE Flow <b>52</b> for each subscriber extends as a portion of the subscriber's ATM virtual circuit, facing the cell relay network and hence the ISPs <b>11</b>. The PPPoE Flow <b>52</b> contains Ethernet frames that are of PPPoE Ethertype. Facing towards the subscriber premises, the switch <b>19</b> implements an Aggregate Flow path <b>53</b>, in the form of another portion of the ATM virtual circuit, which contains all ingress/egress subscriber traffic. The switch implements a Generic Path <b>54</b> extending through the interfaces to the vertical services network. In the first embodiment, this path <b>54</b> carries all traffic other than PPPoE.
0106In this example, the switch <b>19</b> implements the Decision Point <b>51</b> based on recognition of the Ethertype indicator, which is above the layer-2 ATM cell routing information. However, the switch may implement the Decision Point <b>51</b> based on still higher-level protocol information. Also, those skilled in the art will recognize that the concepts of the present invention are applicable in networks using different protocol stacks, for example, based on native IP.
0107In a preferred embodiment, the Ethernet and ATM interfaces <b>41</b> and <b>42</b> and the Ethernet and ATM interfaces <b>44</b> and <b>45</b> implement segmentation and reassemble (SAR) functions, essentially providing two-way conversions between ATM cell format and Ethernet frame format. Segmentation involves dividing an Ethernet frame into a number of 48-byte blocks and adding ATM headers to the blocks to form a corresponding number of ATM cells. Any blocks that do not include a complete 48-byte payload are padded as necessary. Reassembly entails receiving and buffering ATM cells until it is recognized that a complete frame has been received. The ATM headers of the cells and any padding are stripped, and the payload data is reassembled into the form of an Ethernet frame.
0108In such an embodiment of the switch <b>19</b>, the decision point <b>51</b> determines how to selectively forward the Ethernet frame information taken from a particular series of upstream ATM cells based on the Ethernet information taken from the ATM cell payloads, for example, by examining the frame header and recognizing the particular Ethertype indicator. Internally, the actual switch fabric <b>49</b> for such an embodiment of the switch <b>19</b> would comprise an Ethernet switch, even though to other elements of the ADN network <b>10</b> the switch <b>19</b> appears to perform an ATM switching function.
0109Those skilled in the art will recognize however, that the decision and switch fabric may be implemented in other ways. For example, a series of cells corresponding to an Ethernet frame could be buffered and the payloads examined just to recognize and identify the Ethertype indicator, without a complete reassemble of the Ethernet frame. This later implementation therefore could utilize an ATM cell-based switch fabric.
0110From the discussion above, it should already be apparent that certain aspects of the invention relate to setting up logical communication circuits at a relatively low protocol layer corresponding to switching or routing functions and then segregating traffic by distinguishing communication type using higher level protocol information. To insure full understanding on these points, it may be helpful to consider the protocol layer definitions, with particular reference to the illustration of the preferred layers in <figref idref="DRAWINGS">FIG. 2</figref>. The International Standards Organization (ISO) Open Systems Interconnection (OSI) reference model specifies a hierarchy of protocol layers and defines the function of each layer in the network.
0111The lowest layer defined by the OSI model is the physical layer (L1). This layer provides transmission of raw data bits over the physical communication channel through the particular network. For example, on the subscriber lines in the preferred embodiment, the physical layer (L1) uses ADSL. Within the customer premises, communications use an Ethernet physical layer (L1), such as 10Base-T. Upstream network elements may use DS3 at some points, but most use SONET, for example OC-3 or OC-12 physical layer transport. Attention is directed to the lower half of the diagram in <figref idref="DRAWINGS">FIG. 2</figref>, which depicts the various protocol stacks throughout the network <b>10</b>.
0112The layer defined by the OSI model next to the physical layer is the data link layer (L2). The data link layer transforms the physical layer, which interfaces directly with the channel medium, into a communication link that appears error-free to the next layer above, known as the network layer (L3). The data link layer performs such functions as structuring data into packets or frames, and attaching control information to the packets or frames, such as checksums for error detection, and packet numbers. In the network <b>10</b>, the data link layer (L2) is used to define certain switching functions through the network. The network layer (L3) provides capabilities required to control connections between end systems through the network, e.g., set-up and tear-down of connections.
0113The preferred embodiments utilize ATM cell transport as the lowest element of the data link layer (L2), for example to define the connectivity extending from the ATU-Rs <b>23</b> through the ADN network <b>10</b> to the ISP or corporate networks <b>11</b>. Subscriber virtual circuits are provisioned at the ATM cell layer, that is to say at the data link layer (L2). Similarly ISP virtual circuits are provisioned at this ATM data link layer (L2), from the gateway router <b>29</b> through the cell relay network <b>30</b> to the ISP access concentrators <b>31</b>. The ATM protocol therefore is the layer-2 (L2) protocol used to define the logical connectivity from the subscriber premises to the gateway router <b>29</b>. The ATM protocol also is the layer-2 (L2) protocol used to define the logical connectivity from the gateway router <b>29</b> to the ISP concentrators <b>31</b>.
0114For purposes of this discussion, higher level protocols are protocols that ride on or are encapsulated within the particular layer-2 protocol, that is to say in the payloads of the ATM cells in the preferred embodiment. Such higher level protocols include some protocols, which are often considered themselves to be level-2 protocols, where they are transported within ATM cells. The preferred embodiments use Ethernet, a local area network protocol above the ATM portion of the L2 layer. Technically, the Ethernet protocol may be considered as another L2 layer protocol. However, because it is segmented and encapsulated into the payloads of the ATM cells, the Ethernet protocol information actually is a higher level protocol information above the specific level-2 protocol (ATM) that defines the normal connectivity through the ADN network <b>10</b>.
0115In the OSI model, a transport layer protocol (L4) runs above the network layer. The transport layer provides control of data transfer between end systems. Above the transport layer, a session layer (L5) is responsible for establishing and managing communication between presentation entities. For example, the session layer determines which entity communicates at a given time and establishes any necessary synchronization between the entities. Above the session layer, a presentation layer (L6) serves to represent information transferred between applications in a manner that preserves its meaning (semantics) while resolving differences in the actual representation (syntax). A protocol (L7) that is specific to the actual application that utilizes the information communicated runs at the top of the protocol stack.
0116In accord with one inventive concept, the network <b>10</b> actually utilizes two or more different types of protocol at levels above the protocol within the L2 layer that actually defines the network connectivity. The ADN network <b>10</b> may use different protocols at the higher layers as well. By distinguishing transmissions based on differences in these higher-level protocol types, the ATM switch <b>19</b> separately forwards different types of communication traffic for each subscriber. In the preferred embodiment, communications to and from the ISP or corporate networks <b>11</b> utilize point-to-point protocol (PPP) as the network layer (L3) protocol and a shim for transport of PPP over Ethernet (PPPoE). PPPoE, as one Ethertype protocol could also be considered as a second layer (L2) protocol albeit above the Ethernet layer itself, which in turn rides on the ATM cells used for routing at least through the permanent virtual circuit at the L2 layer.
0117In the illustrated implementation, however, the use of the PPPoE or a different protocol actually is an indication of a difference in type of the higher layer protocols. In the illustrated example of <figref idref="DRAWINGS">FIG. 2</figref>, the vertical services domain traffic utilizes Ethernet (802.3 SNAP) above the ATM adaptation layer (AAL). As noted, the presently preferred L3/4 switch <b>19</b> implements its routing decision based on recognition of the Ethertype indicator, that is to say to distinguish the PPPoE traffic from all other types of transmission from the customers' data equipment. In view of the use of ATM as the data link layer (L2) protocol of the network defining the lowest layer of network connectivity for communications services through the ADN network <b>10</b>, the discrimination based on Ethernet actually implements a decision based on an effectively higher protocol layer.
0118IP protocol carries the actual higher-level applications information, for transport to and from the vertical services domain and for transport to and from the wide area internetwork. As such, IP and its related transport protocol referred to as the “Transmission Control Protocol” (TCP) ride on top of (are actually encapsulated within) the lower level protocol elements discussed above. Presentation and application layer elements ride on top of the IP layer. IP communication requires that each user device have an assigned IP address. IP addresses, however, are a scarce commodity. Because of the use of IP transport for both wide area services and vertical domain services, the network <b>10</b> actually may at times assign two different IP addresses to each active data communication device of an end-user, albeit on a temporary basis. The wide area communications and the vertical services network may also be viewed as two separate ‘broadcast’ domains.
0119First, the carrier operating the ADSL data network <b>10</b> and the vertical services domain network <b>13</b> will maintain a pool of local addresses for assignment, on an as-needed basis, to end user equipment <b>25</b>. To the carrier, the available IP addresses are a limited resource. Accordingly, the carrier assigns IP addresses on a dynamic basis, only to those users actually on-line at any given time. The carrier preferably utilizes private network type IP addresses and dynamically administers such addresses using dynamic host configuration protocol (DHCP). DHCP is a protocol for automatic TCP/IP configuration, which enables dynamic address allocation and management.
0120When a particular device <b>25</b> becomes active via the ATU-R <b>23</b> and the DSLAM <b>17</b>, it will activate a basic protocol stack, including an IP portion enabling communication with a DHCP server. The device will transmit an address request upstream through the network on the subscriber's virtual circuit. At the Ethernet level, this transmission appears as a broadcast message. The L3/4 ATM switch <b>19</b>, however, will recognize that the packet is not a PPPoE communication and route the cells carrying the packet into the vertical services domain <b>13</b>. Typically, a DHCP server is coupled to the vertical services domain network <b>13</b>, for example as part of the carrier's administrative network or systems <b>33</b>. The DHCP server somewhere on the vertical services domain <b>13</b>, <b>33</b> will answer that broadcast request by selecting and providing an available one of the private IP addresses from the carrier's pool of available addresses. The message with the assigned address will go back to the L3/4 ATM switch <b>19</b> for insertion into the virtual circuit and transport back to the requesting device <b>25</b>.
0121The particular end-user's device <b>25</b> uses the assigned private IP address as its source address, for all of its communications with the vertical services network <b>13</b>, so long as it remains on-line for the present session. When the overall session ends and the end-user device <b>25</b> goes completely off-line, the DHCP server returns the private IP address to its pool of available addresses, for reassignment to another user as the next user comes on-line.
0122As noted, the user equipment <b>25</b> receives a private IP address from the DHCP server. The addresses of services on the vertical services domain also are private IP networks. Because these addresses are private, they are accessible only to equipment within that domain and the data network <b>10</b>. Consequently, the devices are not accessible to hackers or the like coming in through the public Internet.
0123This dynamic assignment of IP addresses allows the carrier to limit the number of IP addresses used to the number of users actively connected through the ISP's host to the Internet. The use of private IP addresses allows the user equipment to communicate with the vertical services domain utilizing a normal IP-Ethernet protocol stack.
0124For the as-desired Internet access service, for example using a PPP or similar protocol, IP addresses are administered through the ISPs. The PPPoE protocol preserves or emulates the traditional dial-up approach to ISP access. However, the PPPoE approach does utilize Ethernet and follows Ethernet standards, for example, involving processing of certain broadcast messages.
0125The user can select an ISP of choice, and her data equipment <b>25</b> will initiate a selective session through the Ethernet layer on the network <b>10</b> to access the equipment <b>31</b> of the selected ISP network <b>11</b>, in a manner directly analogous to a dial-up modem call through an ordinary telephone network. Hence at a time after initial activation through the networks <b>10</b> and <b>13</b>, the user may activate a browser or other program for using the wide area internetwork service. This activates a second protocol stack, which includes the PPP protocol and the PPPoE shim. The user selects an ISP, and the data equipment initiates communication through the network <b>10</b> to the PPPoE equipment <b>31</b> of that ISP.
0126The IP addresses used by each ISP are public network type IP addresses. To the ISP, the pool of available public IP addresses also is a limited resource. Accordingly, each ISP prefers to assign IP addresses on a dynamic basis, only to those users actually on-line at any given time. Typically, as part of each initial access operation for a PPPoE session, the user's equipment <b>25</b> and the PPP terminating equipment <b>31</b> of the ISP conduct a handshaking, to establish data communications therebetween. As part of this operation, the user's device transmits a broadcast request for a public IP network. The broadcast message, in PPPoE goes through the virtual circuit to the gateway router <b>29</b> and through the router and cell relay network <b>30</b> to the ISPs PPPoE equipment <b>31</b>. Although it is a broadcast message, the network effectively limits transport thereof to the virtual circuit going to the ISPs PPPoE equipment <b>31</b>, that is to a domain separate from the vertical services network domain <b>13</b>.
0127The ISP host equipment <b>31</b> initiates a procedure to assign the user's computer <b>25</b> a numeric Internet Protocol (IP) address from the pool of available public addresses and sends a PPPoE message containing that address back to the subscriber's device <b>25</b>. When the session ends and the user goes off-line, the ISP host can reassign the address to another user, as the next user comes on-line.
0128This dynamic assignment of IP addresses allows the ISP to limit the number of public IP addresses used to the number of users actively connected through the ISP's host to the Internet. The end-user equipment will implement a second protocol stack, carrying PPPoE communications. The PPP protocol will allow the end-user equipment to obtain and utilize the public IP address for communications going to and from the public internetwork.
0129The switch <b>19</b> will limit transport of other types of PPPoE broadcast messages to the link to the PPPoE concentrator <b>31</b>, in a manner similar to that described above for the PPPoE address request. The switch <b>19</b> also limits transport of non-PPPoE broadcast messages to the vertical services domain network <b>131</b>, both for the address request message and for other types of broadcast requests. As such, the logical circuit to the PPPoE concentrator <b>31</b> becomes the conduit to one broadcast domain for upstream PPPoE messages; and the vertical services network <b>13</b> defines a second broadcast domain for upstream messages of other Ethertypes.
0130As noted, the end-user equipment <b>25</b> will implement two protocol stacks, a native stack without PPPoE and a second stack with PPPoE and a shim. In actual operation, both the native stack with other Ethernet protocols and the wide area stack with PPP and the PPPoE shim often will be active at the same time. The software in the data equipment <b>25</b> will utilize one stack or the other depending on whether the user selected a link, e.g. a URL, relating to the wide area internetwork or the vertical services domain. For example, a browser may display a page with embedded links. If a link is to a service on the vertical services domain, the embedded address will be a private address on the vertical services domain. Selection of such a link causes the device <b>25</b> to use the native Ethernet stack (without PPP or PPPoE) and the private address. Hence the L3/4 ATM switch <b>19</b> routes the request triggered by selection of the link to the vertical services domain <b>13</b>. In contrast, if the link is to a service on the public Internet or other network <b>11</b>, the embedded address will be a public IP address. Selection of such a link causes the end-user device <b>25</b> to use the PPP and PPPoE stack and the public address. Hence the L3/4 ATM switch <b>19</b> routes the request triggered by selection of the link over the virtual circuits to the PPPoE equipment <b>31</b> of the currently selected access provider network <b>11</b>.
0131Services provided on the vertical services domain therefore appear as simple IP data services, albeit using the appropriate address space. Virtually any communication service provider may access the vertical services network <b>13</b> and through it the carrier's local customer base simply by providing an IP interface for coupling appropriate equipment to the vertical services network.
0132In addition to vertical services, the carrier continues to provide agreed access services to the equipment of the ISPs, in a manner analogous to current practices. For example, the carrier may provide its Internet access service to a subscriber on a monthly subscription basis, at one of several available rates corresponding to the grade of internet access service (and thus the rate of communication to/from the ISP) selected by the customer's subscription.
0133In an enhanced service offering, the broadcast provider could offer a convenient navigation interface from a web server. The server could be on the vertical services network, but preferably is on the wide area Internet <b>11</b>. With a PPPoE session active, the user can surf to the provider's server and view information about available programming. The user might select a current broadcast program by ‘clicking’ on a URL link in the provider's web-based information. Although provided through the wide area Internet <b>11</b>, the URL would actually contain the private IP address for the desired broadcast program available from the vertical services network <b>13</b>. Selection of such a URL therefore would generate a message to the appropriate server on the vertical services network <b>11</b> to initiate the above discussed procedure to allow the user to ‘join’ the selected broadcast. A similar methodology might also enable a provider to offer menu, selection and order/billing services from the Internet <b>11</b>, to provide pay-per-view or video on-demand type services from the vertical services domain network <b>13</b>.
0134For on-demand content service, such as the downloading of movies, music, games, on-line books, and other bulk on-demand data, the content provider can store such data in a local content server <b>32</b> in the vertical services domain <b>13</b>, as shown in <figref idref="DRAWINGS">FIG. 4B</figref>. In one embodiment, a user might download content stored on the local content server <b>32</b> by entering a URL or selecting a web-based link to the vertical services domain (without PPP or PPPoE) directing the download request to the local content server <b>32</b>. As described above, the content will be transmitted to the end user through the VSI ATM switch <b>19</b>, DSLAM <b>17</b>, and ATU-R <b>23</b>.
0135Certain aspects of the invention relate to distribution of content to or from such a server <b>32</b> in the vertical services domain. The content stored on the local content server <b>32</b> can, in one embodiment, be distributed to the local content server <b>32</b> from a hub site <b>24</b> separated from the central office <b>15</b> by a transmission line <b>27</b>. It is often desirable to distribute content in this manner for many reasons. One such reason is that it is often desirable for content to be distributed or updated frequently. For example, if the content is a movie in a digital format and end users want the most recently released movies, the content on the local content server <b>32</b> must be updated often to include the most recently released movies in digital format. Another reason why it is desirable for content to be distributed through transmission line <b>27</b> is that such a distribution can be automatic and require minimal maintenance by a system administrator at the central office <b>15</b>. One of ordinary skill in the art would recognize other advantages of distributing content from a central content server <b>28</b> to a number of dispersed local content servers <b>32</b>.
0136Typically a hub site <b>24</b>, housing the gateway router <b>29</b>, services several remote central offices <b>15</b>. The hub site <b>24</b> is a prime location for housing a central content server <b>28</b>. The central content server <b>28</b> stores content that is to be distributed to the vertical service domains <b>13</b> of the respective central offices <b>15</b>. Accordingly, a content provider can maintain the content stored on the central content server <b>28</b> and update the local content servers <b>32</b> located at the respective central offices <b>15</b> automatically and periodically. One of ordinary skill in the art would recognize other obvious locations for a central content server on a network.
0137One disadvantage of automatic updating of content on the local content servers <b>32</b> from the central content server <b>28</b>, is that the bandwidth on transmission line <b>27</b> between the hub site <b>24</b> and the central office <b>15</b> is a limited resource. One of ordinary skill in the art would recognize that it is undesirable for content distribution to interfere or compromise the guaranteed transmission rate of subscriber traffic transmitted over transmission line <b>27</b>. A solution to this problem, is a mechanism that determines unused bandwidth over transmission line <b>27</b> and only transmits content from the central content server <b>28</b> to the local content server <b>32</b> using bandwidth that is unused by subscriber traffic. It is desirable to distribute content from a central content server <b>28</b> to a local content server <b>32</b>, but it is undesirable for such distribution to interfere with the quality of subscriber traffic. The mechanism described above only distributes content using unused bandwidth of transmission line <b>27</b> having the advantage of distributing content without interfering with the quality of subscriber traffic.
0138<figref idref="DRAWINGS">FIG. 4C</figref> is an exemplary illustration of bandwidth utilization, in terms of time, for exemplary transmission line <b>27</b>. On the y-axis <b>70</b>, the bandwidth utilization is expressed from 0 to 100%. On the x-axis <b>68</b>, time is expressed in the units of hours, from 0 to 24. As one of ordinary skill in the art would appreciate, the subscriber traffic <b>62</b> varies over time and at times is close to utilizing 100% of the bandwidth of transmission line <b>27</b>. However, at other times subscriber traffic does utilize less than the entire bandwidth of transmission line <b>27</b>. One aspect of the present invention includes a mechanism within the architecture of the hub site <b>24</b> and the central office <b>15</b> to monitor the bandwidth utilization of subscriber traffic <b>62</b>. Using bandwidth utilization information, content distribution <b>64</b> can be implemented over bandwidth unused by subscriber traffic <b>62</b>. Content distribution <b>64</b> fills up the bandwidth of transmission line <b>27</b> when subscriber traffic <b>62</b> utilizes less than 100% of the bandwidth of the transmission line <b>7</b>.
0139It is important to note that region <b>66</b> of <figref idref="DRAWINGS">FIG. 4C</figref> is bandwidth reserved for content distribution. Normally this reserved bandwidth <b>66</b> is minimal and merely serves the purpose of maintaining sessions between the central content server <b>28</b> and local content servers <b>32</b> for content distribution <b>64</b>. The “as-available” bandwidth may use up to the entire capacity of the link <b>27</b> when and if available; or the network may impose a maximum rate limit on the content distribution circuit, e.g., Mb/s.
0140The mechanism for distributing content from the central content server <b>28</b> to the local server <b>32</b> must utilize a congestion mechanism to prevent data loss and utilize unused bandwidth. One such congestion mechanism is Transmission Control Protocol (TCP). TCP employs a window based end-to-end congestion control mechanism to recover from segment loss and also avoid congestion collapse. In one exemplary embodiment, the central content server <b>28</b> is in communication with the gateway router <b>29</b> and the local content server <b>32</b> is in communication with the VSI ATM switch <b>19</b>. This particular mechanism for distributing content from the central content server <b>28</b> to the local content server <b>32</b> is contained in the gateway router <b>29</b> and the VSI ATM switch <b>19</b>, which are both ATM devices capable of prioritizing data transmission.
0141In one exemplary embodiment, a logical circuit is provisioned in the gateway router <b>29</b> and in the VSI ATM switch <b>19</b> for the download traffic between the servers <b>28</b> and <b>32</b>. The provisioning for this logical circuit specifies a guaranteed minimum rate or bandwidth <b>66</b> for “keep-alive” purposes, so that the servers may maintain session communications. The provisioning for this logical circuit also provides an additional transport capacity on an “as available” service, to allow the circuit to access and utilize otherwise unutilized capacity. There may be a set maximum for this “as available” service, or the circuit may be allowed access up to the maximum otherwise unutilized capacity <b>64</b>, at any given time, on the link <b>27</b> between the gateway router <b>29</b> and the VSI ATM switch <b>19</b>. In this manner, the gateway router <b>29</b> and possibly the VSI ATM switch <b>19</b> will throttle the content transmissions from the server <b>28</b> to only consume otherwise available bandwidth as shown at <b>64</b>.
0142In an initial implementation, the logical communication circuit between the servers <b>28</b> and <b>32</b> is an ATM Permanent Virtual Circuit (PVC) between the servers <b>28</b> and <b>32</b>, that is to say extending through the gateway router <b>29</b> and the link <b>27</b> and at least to the access switch <b>19</b>. The provisioning for this ATM circuit specifies the minimum rate or bandwidth <b>66</b> for “keep-alive” purposes and the “as available” capability to access additional bandwidth. In one embodiment, the ATM PVC circuit is provisioned as an Unspecified Bit Rate plus (UBR+) service between the gateway router <b>29</b> and the VSI ATM switch <b>19</b>. The UBR+ service is essentially a low-priority unspecified bit rate service, with certain enhanced features, such as intelligent cell drop and early packet discard. Of note for purposes of discussion here, one of the enhanced features of UBR+ is that it may be provisioned with a minimum rate or service guarantee.
0143Those skilled in the art will recognize that different network implementations may utilize different mechanisms to control congestion and allocate some combination of guaranteed bandwidth and unspecified or as-available bandwidth for the circuit between the servers used for content distribution. For example, it would be possible to provision two circuits, one with low constant bit rate (CBR) service, the other with normal Unspecified Bit Rate (UBR) service. The servers, however, would be configured to treat the two ATM PVC circuits as one aggregate pipe. If router <b>29</b> supports QoS mechanisms of the type described above with respect to service control through the switch <b>19</b>, another alternative is to utilize those mechanisms in the router <b>29</b> and/or the switch <b>19</b>, to implement the desired combination of minimum guaranteed rate and as-available service for the content distribution circuit.
0144One skilled in the art would also recognize the content can be distributed from a local content server <b>32</b> to a central content server <b>28</b> in the same manner as discussed above. One example of when this is desirable, is when the content provider is an end user <b>25</b> served through central office <b>15</b>. Such a content provider would upload content to the local content server <b>32</b> in the respective central office <b>15</b>, and then the content would be distributed from the local content server <b>32</b> to the central content server <b>28</b>. The central content server <b>28</b>, in turn, re-distributes that content to other local content servers <b>32</b>, at other remote central offices <b>15</b>.
0145In one exemplary embodiment, the present invention is a software product for replicating content data from a server <b>28</b> at a hub site <b>24</b> to servers <b>32</b> at a respective central office <b>15</b>. The software product comprises at least one machine readable medium and programming code carried by the at least one machine readable medium for execution by at least one computer. The programming code includes a congestion mechanism and a first transmitting mechanism. The congestion mechanism allows for the determination of unused bandwidth on a portion of a common link of a network over which the hub site and the central office communicate.
0146In one embodiment of the software product, the congestion mechanism is Transmission Control Protocol (TCP) utilized by servers <b>28</b> and <b>32</b>. The congestion mechanism may also rely on UBR+ service or other capabilities through the switches as outlined above. The first transmitting mechanism causes the hub site server to transmit content to a second server, via the otherwise unused bandwidth, e.g. as TCP over UBR+ATM transport.
0147The programming code may further comprise a second transmitting mechanism for causing transmission of content data stored at the central office, e.g. on server <b>32</b>, to the customer. More particularly, the second transmitting mechanism may cause the transmission of the content data stored at the central office to a VSI ATM switch <b>19</b> at the central office <b>15</b>. The second transmitting mechanism then causes the integration of the content data with other data being transmitting to the customer through the ATM switch <b>19</b> in the central office <b>15</b> to the customer equipment <b>25</b>, essentially as described above relative to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>. The second transmitting mechanism may cause the distribution of the integrated data to the customer through a multiplexer.
0148In one embodiment, the software product runs on a server and a gateway router within the hub site and/or the local server and VSI ATM switch of the central office. However, one of ordinary skill in the art would realize that the software product could run from other computer hardware devices within or proximate to the hub site and/or the gateway router. Alternate embodiments of the hub site are discussed later with respect to <figref idref="DRAWINGS">FIG. 7</figref>.
0149Table 2 summarizes the characteristics and requirements of a number of examples of the types of vertical services that the VSD network <b>13</b> can deliver via the L3/4 ATM switch <b>19</b> and the ADSL data network <b>10</b>. <tables id="TABLE-US-00002" num="2"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="3"><colspec colname="1" colwidth="49PT" align="left" /><colspec colname="2" colwidth="84PT" align="left" /><colspec colname="3" colwidth="84PT" align="left" /><thead><row><entry namest="1" nameend="3" align="center">TABLE 2</entry></row><row><entry /></row><row><entry namest="1" nameend="3" align="center" rowsep="1" /></row><row><entry>Vertical</entry><entry /><entry /></row><row><entry>Service</entry><entry>Characteristics</entry><entry>Network</entry></row><row><entry>Offering</entry><entry>of the Service</entry><entry>Requirements</entry></row><row><entry namest="1" nameend="3" align="center" rowsep="1" /></row></thead><tbody valign="top"><row><entry>Voice</entry><entry>Local Co-Located</entry><entry>Low latency, low jitter,</entry></row><row><entry>Services</entry><entry>VoIP Gateways, VoIP,</entry><entry>non-correlated packet</entry></row><row><entry /><entry>Unified messaging,</entry><entry>loss, and high avail-</entry></row><row><entry /><entry>IP PBX, IP Centrex</entry><entry>ability</entry></row><row><entry>Video</entry><entry>Local VOD Servers</entry><entry>High bandwidth, low</entry></row><row><entry>On Demand</entry><entry>or access to central-</entry><entry>jitter, high avail-</entry></row><row><entry>(Unicast)</entry><entry>ized servers. Supports</entry><entry>ability, and low</entry></row><row><entry /><entry>whatever model of</entry><entry>packet loss</entry></row><row><entry /><entry>server deployment/</entry></row><row><entry /><entry>content delivery</entry></row><row><entry /><entry>mechanism.</entry></row><row><entry>Multimedia</entry><entry>Broadcast Video;</entry><entry>Varies with</entry></row><row><entry>Broadcast</entry><entry>Broadcast Audio;</entry><entry>content type and</entry></row><row><entry>(Multicast)</entry><entry>Satellite Down Link</entry><entry>with multicast</entry></row><row><entry /><entry>support; Local</entry><entry>implementation</entry></row><row><entry /><entry>Servers at the edge.</entry></row><row><entry>Caching</entry><entry>Local servers at the</entry><entry>Layer 3/4</entry></row><row><entry>Services</entry><entry>insertion point, Local</entry><entry>visibility</entry></row><row><entry /><entry>delivery mechanism for</entry></row><row><entry /><entry>generic media objects</entry></row><row><entry /><entry>such as web pages,</entry></row><row><entry /><entry>images, video files,</entry></row><row><entry /><entry>audio clips, software</entry></row><row><entry /><entry>downloads, etc.</entry></row><row><entry>Distance</entry><entry>Integrated interactive</entry><entry>Low latency, low jitter,</entry></row><row><entry>Learning</entry><entry>video, voice and data</entry><entry>non-correlated packet</entry></row><row><entry>(EVC)</entry><entry /><entry>loss, and high avail-</entry></row><row><entry /><entry /><entry>ability</entry></row><row><entry>Tele-</entry><entry>Closed user group with</entry><entry>IEEE 802.1Q</entry></row><row><entry>commuting</entry><entry>access to Transparent</entry></row><row><entry /><entry>LAN Service (TLS).</entry></row><row><entry namest="1" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>
0150The above discussed preferred embodiments implemented the processing above the layer-2 protocol in an enhanced ATM switch and focused on implementation over an xDSL network specifically designed for use of twisted pair wiring to the customer premises. Those skilled in the art, however, will recognize that the principles of the present invention are equally applicable to other types of layer-1 and layer-2 transport/switching technologies as well as selection based on other protocols above the layer-2 connectivity protocol.
0151<figref idref="DRAWINGS">FIG. 5</figref>, illustrates the implementation of the layer 3/4 and higher switch functionality in a generic access router (AR) <b>61</b>. The underlying protocol defining the lowest L2 layer switch connectivity may utilize ATM or other transport mechanisms, such as native Ethernet, frame relay, or native IP. The illustration also teaches the provision of digital subscriber line data communication between the access router (AR) <b>61</b> and a number of customer premises, using a variety of line technologies. The digital line technologies include dial-up modems <b>63</b>, <b>65</b> as well as wireless communications between wireless asymmetrical subscriber loop (WASL) transceivers <b>67</b>, <b>69</b>. The access router (AR) <b>61</b> can service residential customers via these other communication technologies as well as through the DSLAM <b>17</b> and the ATU-R <b>23</b> as in the earlier embodiment. The access router (AR) <b>61</b> also serves business customer router equipment <b>71</b>, using a variety of fast frame/cell packet technologies <b>73</b>-<b>76</b> and even optical fiber (SONET) <b>71</b>.
0152Those skilled in the art will recognize that even these examples are limited. For example, the invention may apply to systems that have previously been considered as pure video networks, such as a hybrid fiber-coax implementation of a CATV system with digital video service as well as cable modem service.
0153The access router (AR) <b>61</b> will provide one or more types of logical circuits, implemented in the appropriate layer-2 protocol(s), e.g. ATM, frame relay, etc. Although the links to the wide area internetwork and the vertical services domain have been omitted here for simplicity of illustration, the access router (AR) <b>61</b> will provide the routing functions to and from the wide area internetwork and the vertical services domain in a manner similar to the functionality of the L3/4 ATM switch <b>19</b> in the earlier embodiment. In this regard, the access router (AR) <b>61</b> will support the QoS levels and will enable local insertion of vertical services.
0154<figref idref="DRAWINGS">FIG. 6</figref> depicts a portion of the network of <figref idref="DRAWINGS">FIG. 5</figref>, showing the interconnection thereof with the wide area internetwork and the local vertical services domain. The vertical services network itself may include a number of routers (R) <b>73</b>. Through that network, the access router (AR) <b>61</b> provides communications with services in the VSD that may be purely local, somewhat distributed or even centralized. True long distance data services, such as chat rooms, email and web browsing on the public Internet, however, are considered as Off-Net services, since they are accessed via the Internet access connection under the associated SLA.
0155Although the embodiments discussed to this point provide a single local vertical services domain and the public Internet domain through the ISPs or ISPs, the inventions encompass networks supporting even more distinct network domains. For example, the different Ethertype identifiers or other traffic type indicators can be used to segregate traffic into multiple domains at different points between the DSLAM and the gateway router. The PC or other CPE would determine which type to use, and a switch similar to the VSI switch <b>19</b> at the appropriate point along the PVC would segregate and aggregate the traffic according to Ethertype or the like. In addition, the distinctions can be based on still higher types of information from the protocol stack.
0156<figref idref="DRAWINGS">FIG. 7</figref> illustrates a somewhat modified architecture of the ADN and may be helpful in understanding certain aspects and alternatives relating to the inventive content distribution as well as the implementation of more network domains. The drawing shows two central offices <b>15</b><sub>1 </sub>and <b>15</b><sub>2 </sub>and the hub site <b>24</b>. It should be noted, however, that the hub <b>24</b> typically is located in a central office, as well. Each of these central offices includes one or more DLAMS <b>17</b>, a VSI ATM switch <b>19</b> and a local vertical services domain network <b>13</b>. In general, these elements provide Internet access and vertically inserted services through modems (ATU-Rs) <b>23</b> to customer premises equipment (not shown here for simplicity of illustration).
0157For example, the first remote central office <b>15</b><sub>1 </sub>includes one or more DLAMS <b>17</b><sub>1 </sub>and a VSI ATM switch <b>19</b><sub>1</sub>. The DSLAMS <b>17</b><sub>1 </sub>provide DSL communications to and from the customer premises modems <b>23</b><sub>1</sub>. The first remote central office <b>15</b><sub>1 </sub>also includes a local data network forming the first vertical services domain <b>13</b><sub>1</sub>. Data equipment for providing the vertically inserted services connects to the vertical services domain <b>13</b><sub>1</sub>. Of note for purposes of this discussion, the equipment connected to the vertical services domain <b>13</b><sub>1 </sub>includes a local content server <b>32</b><sub>1</sub>, for example for content downloading as might be used in an on-demand service or the like. Similarly, the second remote central office <b>15</b><sub>2 </sub>includes one or more DLAMS <b>17</b><sub>2 </sub>and a VSI ATM switch <b>19</b><sub>2</sub>. The DSLAMS <b>17</b><sub>2 </sub>provide DSL communications to and from the customer premises modems <b>23</b><sub>2</sub>. The first remote central office <b>15</b><sub>2 </sub>also includes a local data network forming the second vertical services domain <b>13</b><sub>2</sub>. Data equipment for providing the vertically inserted services, such as the local content server <b>32</b><sub>2</sub>, connects to the vertical services domain <b>13</b><sub>2</sub>.
0158These elements in the remote central offices <b>15</b><sub>1 </sub>and <b>15</b><sub>2 </sub>function essentially the same as in the earlier embodiments, to provide both Internet access services and vertically inserted services, including content distribution to customers. In particular, the VSI ATM switches <b>19</b><sub>1</sub>, <b>19</b><sub>2 </sub>forward upstream PPPoE traffic over the respective SONET links <b>27</b> to the hub office <b>24</b> and segregate upstream traffic of at least one other Ethertype and supply that traffic to the respective vertical services domain <b>13</b><sub>1</sub>, <b>13</b><sub>2</sub>. In the downstream direction, the VSI ATM switches <b>19</b><sub>1</sub>, <b>19</b><sub>2 </sub>aggregate traffic from the respective vertical services domain <b>13</b><sub>1</sub>, <b>13</b><sub>2 </sub>together with respective customers' Internet traffic in the virtual circuits, for communication via the DSLAMS <b>17</b><sub>1</sub>, <b>17</b><sub>2 </sub>and modems <b>23</b><sub>1</sub>, <b>23</b><sub>2 </sub>to the customer premises equipment.
0159As noted, the remote hub site <b>24</b> also is within the building of a central office. The hub office may provide tandem services, but in most cases, the hub office will also provide at least some end office services over subscriber links to customer premises. Accordingly, the office <b>24</b> also includes one or more DLAMS <b>17</b><sub>3 </sub>and a VSI ATM switch <b>19</b><sub>3</sub>. The DSLAMS <b>17</b><sub>3 </sub>provide DSL communications to and from the customer premises modems <b>23</b><sub>3</sub>. The hub office <b>24</b> also includes at least one and preferably two local network domains. The first of the local domains in the hub <b>24</b> is a local data network forming a third vertical services domain <b>13</b><sub>3</sub>. Data equipment for providing the vertically inserted services for example, including a content server <b>32</b><sub>3</sub>, connects to that vertical services domain <b>13</b><sub>3</sub>. In this embodiment, the content server <b>32</b><sub>3 </sub>provides local content distribution services to customer equipment coupled to the ATU-R modems <b>23</b><sub>3</sub>, in essentially the same manner as provided by the content servers <b>32</b> in the other offices <b>15</b>. As discussed more later, a central content server <b>28</b> in the office <b>24</b> also provides distribution of content to/from the servers <b>32</b>.
0160With respect to the locally served customers, for example receiving services via the ATU-R modems <b>23</b><sub>3</sub>, the elements <b>17</b><sub>3</sub>, <b>19</b><sub>3 </sub>and <b>13</b><sub>3 </sub>function essentially the same as in the earlier embodiments, to provide both Internet access services and vertically inserted services, including content distribution to those customers. In particular, the VSI ATM switch <b>19</b><sub>3 </sub>forwards upstream PPPoE traffic toward the Internet, and switch <b>19</b><sub>3 </sub>segregates upstream traffic of at least one other Ethertype and supplies that traffic to the vertical services domain <b>13</b><sub>3</sub>. In the downstream direction, the VSI ATM switch <b>19</b><sub>3 </sub>aggregates traffic from the vertical services domain <b>13</b><sub>3 </sub>together with the respective customers' Internet traffic in the virtual circuits, for communication via the DSLAMS <b>17</b><sub>3 </sub>and the modems <b>23</b><sub>3 </sub>to the customer premises equipment.
0161The hub office <b>24</b>, however, also implements a number of centralized functions. As in the earlier embodiments, the hub office <b>24</b> provides the link to the Internet, for example, via a gateway router <b>29</b>. The drawing shows the router in dotted line form, because the use of such router in this embodiment is optional and may no longer be necessary. Preferably, the VSI ATM switch <b>19</b><sub>3 </sub>implements the functions previously performed by the gateway router <b>29</b>, in addition to the functions discussed above relative to the switches <b>19</b>. To this end, the VSI ATM switch <b>19</b><sub>3 </sub>includes interface cards for trunk connections <b>27</b> going to/from the other switches <b>19</b><sub>1</sub>, <b>19</b><sub>2</sub>. The VSI ATM switch <b>19</b><sub>3 </sub>further includes one or more interface cards for trunk connection(s) to the public ATM network <b>30</b>, which provides the links to the Internet service providers.
0162The hub office <b>24</b> also provides a convenient location to implement the network services domain <b>33</b> and provide associated network server(s) <b>34</b>. The server <b>34</b>, for example, may provide the above-discussed DHCP address administration for the ADN carrier's vertical services. The server <b>34</b> also may perform a variety of network operations in support of the ADN, such as automated provisioning, downloading of network related software to CPE devices, automated testing, etc. The central content distribution server <b>28</b> may connect to the vertical services domain <b>13</b><sub>3 </sub>in the hub <b>24</b>; or as shown, that server <b>28</b> may connect to the network services domain.
0163The earlier embodiments supported two network domains, one for Internet services and the other for vertical services. The embodiment of <figref idref="DRAWINGS">FIG. 7</figref> implements a traffic-type routing technique, as an extension of that used in the earlier embodiments, to implement even more distinct network domains. For example, different Ethertype identifiers can be used to segregate traffic into multiple domains at different points in the ADN. Specifically, the respective end offices implement PPPoE segregation of upstream traffic on the subscribers' logical circuits, for all traffic going to the Internet. The PC or other CPE uses a second Ethertype indicator in traffic destined for the vertical services domain <b>13</b> in the respective office <b>15</b> or <b>24</b>. The VSI ATM switch <b>19</b> extracts upstream traffic of an appropriate second Ethertype from the logical circuits for the respective local subscribers and supplies that traffic to the network forming the vertical services domain <b>13</b> in the respective office.
0164The network of <figref idref="DRAWINGS">FIG. 7</figref> utilizes a third Ethertype for traffic relating to the network services domain <b>33</b>. The PC or other CPE uses the third Ethertype indicator in traffic destined for equipment in the network services domain <b>33</b>, such as the network server <b>34</b>. The VSI ATM switches <b>19</b><sub>1</sub>, <b>19</b><sub>2 </sub>in the remote central offices <b>15</b><sub>1</sub>, <b>15</b><sub>2</sub>, allow this traffic type to pass upstream over the trunk links <b>27</b> in the subscribers' logical circuits, together with the PPPoE traffic. The VSI ATM switches <b>19</b><sub>3</sub>, however, extracts upstream traffic of the third Ethertype from the logical circuits for the respective local subscribers and supplies that traffic to the network forming the network services domain <b>33</b> in the hub office. The switch <b>19</b><sub>3</sub>, performs this Ethertype recognition and traffic segregation both for upstream traffic received via the trunk links <b>27</b> and for traffic of the local subscribers coming over logical circuits from the ATU-R modems <b>23</b><sub>3</sub>. As noted earlier, the traffic type distinctions can be based on still higher types of information from the protocol stack.
0165The switch <b>19</b><sub>3 </sub>also aggregates downstream traffic from the network services domain <b>33</b> into the appropriate customers' logical circuits. The remote switches <b>19</b><sub>1</sub>, <b>19</b><sub>2 </sub>allow such traffic to pass downstream within the respective customers' logical circuits, in essentially the same manner as downstream traffic coming from the Internet.
0166In this manner, the network of <figref idref="DRAWINGS">FIG. 7</figref> provides Internet access services, vertical services insertion and network services in a manner analogous to the earlier embodiments. Certain services, such as content distribution and network services, however, can be centralized to at least to some extent in the hub office <b>24</b>. The use of a VSI ATM switch <b>19</b><sub>3 </sub>at the hub <b>24</b> also allows application of the prioritization and queuing for QoS, at the hub location.
0167The preferred embodiment shown in <figref idref="DRAWINGS">FIG. 7</figref> offers certain advantages of particular note with respect to the inventive content distribution. In that embodiment, content is distributed among the servers <b>28</b>, <b>32</b>. The content may be uploaded from a server <b>32</b> to the central content server <b>28</b>, but most often content is downloaded from the central server to one or more of the local content servers <b>32</b>. For this purpose, the network of <figref idref="DRAWINGS">FIG. 7</figref> provides at least one logical circuit between the central content server <b>28</b> and each of the local content servers <b>32</b><sub>1</sub>, <b>32</b><sub>2</sub>. The servers utilize a congestion mechanism to prevent data loss and utilize unused bandwidth, such as Transmission Control Protocol (TCP). Each logical circuit between two content servers preferably is provisioned to have a guaranteed minimum rate or bandwidth <b>66</b> for “keep-alive” purposes, as well as an additional “as available” transport capacity. There may be a set maximum for the “as available” service, or the circuit may be allowed access up to the maximum otherwise unutilized capacity <b>64</b>, at any given time, on the link <b>27</b> between the switch <b>19</b><sub>3 </sub>and the VSI ATM switch <b>19</b><sub>1 </sub>or <b>19</b><sub>2 </sub>in the respective remote office <b>15</b> (see <figref idref="DRAWINGS">FIG. 4C</figref>).
0168In this regard, it may be helpful to discuss one specific example of such a circuit between content servers. For that purpose, consider the circuit between the central content server <b>28</b> in the hub site <b>24</b> and the first local content server <b>32</b><sub>1 </sub>in the remote central office <b>15</b><sub>1</sub>. The circuit may be an ATM permanent virtual circuit extending through the hub VSI ATM switch <b>19</b><sub>3</sub>, the appropriate interoffice link <b>27</b> and the first remote VSI ATM switch <b>19</b><sub>1</sub>. In one embodiment, the ATM PVC circuit is provisioned as an Unspecified Bit Rate plus (UBR+) service. The provisioning for this ATM circuit in the switches <b>19</b><sub>1</sub>, <b>19</b><sub>3 </sub>specifies the minimum “keep-alive” rate or bandwidth <b>66</b> and the “as available” capability parameters <b>64</b>.
0169The embodiment of <figref idref="DRAWINGS">FIG. 7</figref>, however, also will support a preferred alternative implementation of the logical circuit between the central content server <b>28</b> and each of the local content servers <b>32</b><sub>1</sub>, <b>32</b><sub>2</sub>. In this later embodiment, the circuit again would extend through the hub VSI ATM switch <b>19</b><sub>3</sub>, the appropriate interoffice link <b>27</b> and the first remote VSI ATM switch <b>19</b><sub>1 </sub>and use an ATM PVC. However, the circuit is provisioned as a normal Unspecified Bit Rate, with no guaranteed minimum. Instead, the desired rate characteristics are implemented using the prioritization and queuing mechanisms developed for QoS and described earlier. At least the hub switch <b>19</b><sub>3 </sub>applies the QoS mechanisms to the communications between the servers in such as manner as to implement the desired available bandwidth service with a minimum guarantee for transmissions from the central server <b>28</b> to the remote server <b>32</b>. If appropriate, the switch <b>19</b><sub>1 </sub>may provide similar bandwidth regulations using its QoS mechanisms, for transmissions from the content servers <b>32</b><sub>1 </sub>to the central server <b>28</b>.
0170The use of the VSI ATM switch at the hub also provides another point for cell replication. For example, the switch <b>19</b><sub>3 </sub>can replicate cells for concurrent transmission to the remote switches <b>19</b><sub>1 </sub>and <b>19</b><sub>2</sub>. The switches <b>19</b><sub>1 </sub>and <b>19</b><sub>2 </sub>can supply such content to servers in the associated vertical services domains <b>13</b>. Alternatively, the switches <b>19</b><sub>1 </sub>and <b>19</b><sub>2 </sub>can further replicate cells for transmission to currently “joined” customers of a broadcast service.
0171While the foregoing has described what are considered to be the best mode and/or other preferred embodiments of the invention, it is understood that various modifications may be made therein and that the invention may be implemented in various forms and embodiments, and that it may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the inventive concepts.
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| US8161178B2 | Cited by | United States of America | Applicant |
| US11076189B2 | Cited by | United States of America | Applicant |
| US11088999B2 | Cited by | United States of America | Applicant |
| US9674224B2 | Cited by | United States of America | Applicant |
| US10136172B2 | Cited by | United States of America | Applicant |
| US10404758B2 | Cited by | United States of America | Applicant |
| US11109090B2 | Cited by | United States of America | Applicant |
| US11381549B2 | Cited by | United States of America | Applicant |
| US10638361B2 | Cited by | United States of America | Applicant |
| US2010211476A1 | Cited by | United States of America | Pre-grant |
| US11032518B2 | Cited by | United States of America | Applicant |
| US11412320B2 | Cited by | United States of America | Applicant |
| US11665509B2 | Cited by | United States of America | Applicant |
| US11563995B2 | Cited by | United States of America | Applicant |
| US11122316B2 | Cited by | United States of America | Applicant |
| US2012281706A1 | Cited by | United States of America | Pre-grant |
| US12081817B2 | Cited by | United States of America | Applicant |
| US11609972B2 | Cited by | United States of America | Applicant |
| US2010009659A1 | Cited by | United States of America | Pre-grant |
| US10965727B2 | Cited by | United States of America | Applicant |
| US10432990B2 | Cited by | United States of America | Applicant |
| US10411939B2 | Cited by | United States of America | Applicant |
| US11831955B2 | Cited by | United States of America | Applicant |
| US10069836B2 | Cited by | United States of America | Applicant |
| US9961413B2 | Cited by | United States of America | Applicant |
| US11606380B2 | Cited by | United States of America | Applicant |
31 members in 3 offices
Priority claims10
| Document | Office | Kind | Date |
|---|---|---|---|
| 63569500 | United States of America | A | |
| 63569500 | United States of America | A | |
| 83564901 | United States of America | A | |
| 83564901 | United States of America | A | |
| 61293506 | United States of America | A | |
| 09635695 | – | – | – |
| 09835649 | – | – | – |
| US20000635695 | – | – | – |
| US20010835649 | – | – | – |
| US20060612935 | – | – | – |
Members31
| Document | Office | Kind | |
|---|---|---|---|
| WO0214977A2 | World Intellectual Property Organization (WIPO) | A2 | |
| WO0214978A2 | World Intellectual Property Organization (WIPO) | A2 | |
| WO0214979A2 | World Intellectual Property Organization (WIPO) | A2 | |
| WO0214980A2 | World Intellectual Property Organization (WIPO) | A2 | |
| WO0215492A1 | World Intellectual Property Organization (WIPO) | A1 | |
| WO0215493A1 | World Intellectual Property Organization (WIPO) | A1 | |
| WO0215494A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU7921801A | Australia | A | |
| AU7921901A | Australia | A | |
| AU7923401A | Australia | A | |
| AU8315101A | Australia | A | |
| AU8321001A | Australia | A | |
| AU8321301A | Australia | A | |
| AU8321401A | Australia | A | |
| US2002044567A1 | United States of America | A1 | |
| WO0214977A3 | World Intellectual Property Organization (WIPO) | A3 | |
| WO0214978A3 | World Intellectual Property Organization (WIPO) | A3 | |
| US6424657B1 | United States of America | B1 | |
| WO0214980A3 | World Intellectual Property Organization (WIPO) | A3 | |
| WO0214979A3 | World Intellectual Property Organization (WIPO) | A3 | |
| US6778525B1 | United States of America | B1 | |
| US6798751B1 | United States of America | B1 | |
| US6829250B2 | United States of America | B2 | |
| US6904054B1 | United States of America | B1 | |
| US7042880B1 | United States of America | B1 | |
| US2006098670A1 | United States of America | A1 | |
| US7170905B1 | United States of America | B1 | |
| US2007124488A1 | United States of America | A1 | |
| US7801158B2 | United States of America | B2 | |
| US2011069619A1 | United States of America | A1 | |
| US8885487B2 | United States of America | B2 |
23 transactions on the USPTO file
Abandoned after 1 non-final rejection.
- Non-final rejections
- 1
- Final rejections
- 0
- RCEs
- 0
- Appeals
- 0
Over time
Point at a mark for the transactionTransactions
| Event | Code | |
|---|---|---|
| Email NotificationEML_NTR | EML_NTR | |
| Mail Abandonment for Failure to Respond to Office ActionAbandonedMABN2 | MABN2 | |
| Aband. for Failure to Respond to O. A.AbandonedABN2 | ABN2 | |
| Electronic ReviewELC_RVW | ELC_RVW | |
| Email NotificationEML_NTF | EML_NTF | |
| Mail Non-Final RejectionNon-final rejectionMCTNF | MCTNF | |
| Non-Final RejectionNon-final rejectionCTNF | CTNF | |
| Case Docketed to Examiner in GAUDOCK | DOCK | |
| Case Docketed to Examiner in GAUDOCK | DOCK | |
| Case Docketed to Examiner in GAUDOCK | DOCK | |
| Case Docketed to Examiner in GAUDOCK | DOCK | |
| Case Docketed to Examiner in GAUDOCK | DOCK | |
| Transfer Inquiry to GAUTI1050 | TI1050 | |
| PG-Pub Issue NotificationPG-ISSUE | PG-ISSUE | |
| IFW TSS Processing by Tech Center CompleteTSSCOMP | TSSCOMP | |
| Mail Post CardPST_CRD | PST_CRD | |
| Email NotificationEML_NTF | EML_NTF | |
| Application Dispatched from OIPEOIPE | OIPE | |
| Application Is Now CompleteCOMP | COMP | |
| Cleared by L&R (LARS)L128 | L128 | |
| Referred to Level 2 (LARS) by OIPE CSRL198 | L198 | |
| IFW Scan & PACR Auto Security ReviewSCAN | SCAN | |
| Initial Exam Team nnIEXX | IEXX |
2 recorded assignments at the USPTO, latest first
- Now
Now: Held by
VERIZON PATENT AND LICENSING INC - 2014-05-08
Assignment of assignors interest.
Ownership change- From
- VERIZON COMMUNICATIONS INC
- To
- VERIZON PATENT AND LICENSING INC
Recorded 2014-05-08, Signed 2014-04-09
- 2012-04-04
Assignment of assignors interest.
Ownership change- From
- BAUM ROBERT TVOIT ERIC A
- To
- VERIZON COMMUNICATIONS INC
Recorded 2012-04-04, Signed 2001-04-06
3 legal events, as the office reported them to INPADOC
Over the term
Point at a mark for the eventEvents
| Event | Code | |
|---|---|---|
| AssignmentAS | AS | |
| AssignmentAS | AS | |
| Information on status: application discontinuationABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTIONSTCB | STCB |
Numbers
- Publication
- 20070124488
- Publication, DOCDB
- 2007124488
- Publication, EPODOC
- US2007124488
- Application
- 11612935
- Application, DOCDB
- 61293506
- Application, EPODOC
- US20060612935
Titles
- English
- Vertical Services Integration Enabled Content Distribution Mechanism
Classification
- CPC, 7
- H04Q11/0478
- H04L47/2408
- H04L2012/561
- H04L2012/5632
- H04L2012/5658
- H04L2012/5667
- H04L2012/5672
- IPC, 3
- G06F15 16
- H04L12 56
- H04Q11 04
- USPC, 1
- 709230000