Network management device and method for setting up a logical link in a synchronous digital transmission system

p0001The invention relates to a network control means for establishing a logical connection in a digital synchronous communications network according to the preamble of claim 1 and a method according to the preamble of claim 8.

p0002Existing digital synchronous message-transmission networks such as SDH or SONET networks (SDH: Synchronous Digital Hierarchy, SONET: Synchronous Optical Network) are static networks, ie logical connections in the communication network to be set up permanently by a management system, more or less.

p0003In the article "Network Planning and Management", O. Gonález Soto et al, Electrical Communication, Alcatel, issue 4/1993, pages 366-377 it is disclosed that a certain flexibility to cover unexpected yet about change in SDH networks by providing a certain oversupply is achieved. Through online management processes this oversupply can temporarily, ie for the period ranging from several days to several months are used.

p0004Setting up logical connections in the SDH network is then in a network planning due to forecasts of demand for several years. For network planning the SDH network is divided into subnetworks that are optimized separately. The optimization is carried out in two management layers by means of a routing method that can estimate the cost of individual way and taken into account.

p0005After completion of the network planning of the online management process generated in the case that the capacity limit established connection is achieved on the lower layer management a provisioning request. If the capacity of lower administrative layer is depleted, a provisioning request is directed to the process of path means the top management layer, where they can be carried out automatically or by operators. Such provisioning requests are limited to the subnets and the individual network operators. In addition, only bottlenecks in the period of several days can be considered with this type of adjustment. Frequent short-term bottlenecks can only be addressed by sustainable provision of additional transmission capacity, but then remains unused for long periods until the times of shortages.

p0006From US 5,629,938 an access network type SONET digital cross-connects is known on customer request from a control computer automatically fixed, dedicated connections are established in the. Customer requirements can be entered manually through a job center or the customer can transmit corresponding commands directly electronically via the same access network to the control computer. The latter requires changes to existing network elements and the standardization of an appropriate signaling protocol.

p0007The object of the invention is to provide a power control device and a method for establishing logical connections in a synchronous digital data transmission network, which allow better utilization of existing transmission capacities and can be realized with simple means.

p0008The object is achieved with regard to the power control device by the features of claim 1 and in terms of the method by the features of claim 8. Advantageous embodiments are disclosed in the dependent claims.

p0009The invention is particularly for the construction of leased lines, so-called leased lines, advantageous and useful. In addition to the better utilization of existing transmission capacity, the invention has the further advantages that communications networks flexibly to currently

p0010prevailing demand can be adapted and that communications networks are more user friendly and better adapted to users' needs.

p0011Claim 6 describes a particularly advantageous development of the invention, which makes it possible that desired by a client connection parameters are specified, such as priority, bandwidth, desired point in time the provision of the requested connection, desired duration of the provision of the requested connection and / or desired safety and quality characteristics of the requested connection. This opens up the operators of digital synchronous communications networks or -teilnetze new businesses by automatic means temporary leased line (so-called leased lines) at a given time with predetermined characteristics is made possible.

p0012In the following an embodiment of the invention will be explained with reference to FIGS 1 and 2. FIG. It shows:<dl id="dl0001" compact="compact"><dt>figure 1</dt><dd>a schematic representation of the management structure of a digital synchronous communications network comprising a network control device according to the invention and</dd><dt>figure 2</dt><dd>a flow chart of the inventive method.</dd></dl>

p0013A basic idea of ​​the invention is to provide a network controller that is able to receive individual connection requests to select for such a connection request a path through the communications network and to initiate the setup of the requested connection over the selected path.

p00141 shows the hierarchical structure of the management of a digital synchronous communications network is illustrated schematically. A communications network consists of different network elements such as cross-connect systems DXC and add / drop multiplexers ADM that are intermeshed through physical connections such as fiber optic or coax Kobel to a network.

p0015For a number of similar network elements of a subnetwork, respectively, there is a network element management device SH. This is network element-specific functions, such as turning on a compound responsible, as well as for network element-specific messages and alarms for control and monitoring. The network element management facilities of a subnet are connected to a regional management device, the so-called regional manager RM. This controls the connection setup, the network planning and optimization in the subnet. The Regional Manager of subnetworks are connected to a higher-level management device, known as Country Manager CM. This higher-level management device CM administered, for example, the communications network of a country or an operator.

p0016According to a network controller NSE is provided for setting up logical connections. The Netuteverungseinrichtung NSE is connected to the Country Manager CM. It has access means in the form of an Internet interface INET, on a customer KD may send a connection request to the network controller. The connection request contains the order to establish a logical connection within the communications network, for example, a leased line from Stuttgart to London. The network controller then selects by a selection means suitable for a logical connection to path, for example by means of a processor with associated program memory in which a Selection algorithm abarbeitendes Auswahlprogromm stored.

p0017The selection of the path can be done in several ways: One possibility is that the network control device has a memory, are stored in the data on the structure of the communications network. From these data, the possible, that existing in the communications network paths are determined. About the connection to the Country Manager CM the current load can be obtained now for any path, based on the then selecting the most appropriate path is taken. It is also possible to determine a cost parameter for each possible path, taking into account the current load and for example the length of the path. The selection is then made such that the most cost-effective connection is selected. the data on the structure of the communications network in the memory are advantageously stored in the form of a routing table.

p0018Another possibility for the selection of the path is the connection request in parameterized form, for example in the form of start and end point of the compound to pass the country manager, which then determines possible paths and it returns as a result to the network control device. From these possible paths can for example also be based on a cost parameter a selection of the most appropriate path done.

p0019The network control device NSE has means for causing the connection establishment of the logical connection to be set up via the selected path. This includes an interface device which is connectable to the country manager. This may be, for example, by a specified for management purposes in SDH interface Q act (ITU-T G.773, march 1993). Via this interface, instructions are sent to the country manager to establish the logical connection to be over the selected path. Advantageously, the network controller NSE additional interfaces to Country Managers of other operators or countries. This is a cross-border connection involving various operators made possible by can be queried via the additional interfaces information on the structure and utilization of adjacent communication networks.

p0020According to an advantageous embodiment of the invention, the access means are suitable in addition to the connection request can also be received from a Authentikationsinformationen Customers eröglichen, clearly establish the identity of the client and verify. For this purpose, means are provided for checking the Authentikationsinformationen in the network control device. This ensures that only authorized customers send a connection request to the network controller. In addition, an automatic billing of costs incurred for the connection charge is made possible in a corresponding account. The authentication can be done for example by means of a smart card of the customer, on the Authentikationsinformationen and keys are stored.

p00212 shows a flowchart of the method according to the invention is shown. The following steps are performed:<dl id="dl0002" compact="compact"><dt>Step S1:</dt><dd>A connection request for a logical connection is received by a customer through an internet hotline.</dd><dt>Step S2:</dt><dd>There are determined all the possible paths in the communications network, as candidates for the construction of the logical link in question and have the spare capacity. From the possible paths, one is chosen for the connection. This is preferably done by a cost parameters as a function of the length, the number zwischengeschalter network elements and the utilization of einzelen path segments is determined for each possible path and the lowest cost path is selected.</dd><dt>Step S3:</dt><dd>The structure of the logical link on the selected path is caused by the instruction to establish the logical connection the path parameters on the country manager to be forwarded. The connection itself is then of the management bodies with the help of so-called "managed Objecis" performed as described in the article by MP Bosse et al, "Management of SDH network elements: an application of information modeling". In Electrical Communication, Alcatel, Issue 4/1993, Pages 329-338 indicated.</dd></dl>

p0022Between the step S1 and the step S2 may advantageously in a further step S1A an authentication of the customer are made. Therefore the client transmits encrypted Authentikationsinformationen to the network controller, which then checks the Authentikationsinformationen to determine the identity and authorization of the customer and verified. The authentication can be done for example by means of a smart card of the customer, on the Authentikationsinformationen and keys are stored.

p0023A particularly advantageous development of the invention permits required by a client connection parameters are specified as priority, bandwidth, desired date that the requested connection, desired duration of the provision of the requested connection and / or desired safety and quality features of the requested connection. These connection parameters are taken into account by the network control device when selecting an appropriate path. Is an appropriate path is found, the network controller sends back an acknowledgment signal to the client that contains the actual connection parameters of the connection.

p0024The network controller includes a memory that stores the connection requirements of different customers to the execution of each connection request. This is advantageous because in the path search other currently open, ie not yet completed, connection requests are taken into account, the wish for example to connect a overlapping period. Below some examples of connection parameters are listed, which could indicate a customer:<ul><li>High priority:<ul><li>instant connection or at the latest in X seconds or minutes</li><li>Connection establishment for a period of X hours from the time of the confirmation of</li></ul></li><li>Medium priority:<ul><li>Connection within a day even during peak business hours (9:00 to 17:00)</li><li>Connection during a predetermined period of time during off-peak time. The time will be announced 12 hours in advance.</li></ul></li><li>Low priority:<ul><li>Connection sometime during off-peak hours (at night).</li></ul></li></ul>

p0025The network control means has output means, in the form of a Web interface to the customer by means of which a confirmation signal is sent with the actual Verbindungsporametern to the customer. This Bestötigungssignal be seen from the actual time of connecting the customer then, for example. Advantageously, the cost parameter is calculated as a function of the actual connection parameters. This cost parameters can be used in addition to the selection of a path also for charging for the customer. This enables the network controller also handles the billing. Operators of digital synchronous communications networks or -teilnetze open up new business by automatic means temporary leased line (so-called leased lines) is possible at any given time with a given bandwidth and security features. In addition, the flexibility of the network is increased for the customer, since it now can order temporary connections, which was not possible with previous leased lines.