Facilitating synchronization of servers in a coordinated timing network

(54) Title: EQUIPMENT AND COMPUTER PROGRAM METHOD TO FACILITATE THE SYNCHRONIZATION OF SEVRIDORS IN A CONJUGATED OPERATION NETWORK (30) Unionist Priority: 31/01/2007 us 60 / 887,584 (73) Holder (s): International Business Machines

CORPORATION (72) Inventor (s): david elko, david whitney, denise SEVIGNY, DENNIS J. DAHLEN, DONALD CRABTREE, JUDITH WIERBOWSKI, MICHEL HACK, NOSHIR DHONDY, Ronald Smith, Scott Carlson (74) Attorney (s): Ricardo de Andrade Bergamo da Silva (57) Abstract: COMPUTER method, equipment and program to FACILITATE SERVER SYNCHRONIZATION IN A CONJUGATED OPERATION NETWORK. A jointly operated network is provided, which includes a plurality of servers. The network servers obtain information used to keep the servers in time synchronization, thus ensuring the integrity of the servers.

(86) International Order: pct EP2008050620 of 01/21/2008 (87) International Publication: wo 2008 / 092764of 07/08/2008

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METHOD, EQUIPMENT AND COMPUTER PROGRAM TO FACILITATE SERVER SYNCHRONIZATION IN A CONJUGATED OPERATION NETWORK

TECHNICAL FIELD

This invention relates, in general, to time synchronization within and between a network of processing units and in particular, to define a network of joint operation and to give a definition of the network to the servers of the network to facilitate the synchronization of the servers.

BACKGROUND OF THE INVENTION

For performance and data integrity, systems that access shared data, such as the Computing Sysplex offered by the International Business Machines Corporation, Armonk, New York, must be able to maintain the time of day (TOD) clock synchronization with an accuracy that is best of the best communication process time between systems. Currently, an example, to satisfy the synchronization requirements, a timer, such as the IBM Sysplex Timer ®, is used. This timer requires expensive dedicated Timing links and a separate external box. IBM ® and IBM Sysplex Timer ® are registered trademarks of International Business Machines Corporation, Armonk, New York.

Networks, such as network timing protocol (NTP), provide time synchronization, but do not meet the precision requirements of high-quality systems. NTP requires that each server has access to an external source of time that provides precision to a microsecond level in order to ensure all servers synchronize at the same time. This is an issue for systems that do not have an ability to attach to external time servers that provide that level of accuracy. In addition, a requirement for GPS receivers or a similar attachment in each system can be considered in computational, for reasons of maintenance, safety and reliability.

SUMMARY OF THE INVENTION

-2 / 64Based on the above, there is a need for a feature that facilitates the provision of time synchronization. An example, there is a need for a resource that defines a calendar network and allows that definition to be obtained by servers on the network and used to provide time synchronization.

The deficiencies of the prior art are overcome and additional advantages are provided through the provision of an article of manufacture that includes at least one usable computer medium having the logic of the computer's readable code program to facilitate the synchronization of servers on a calendar network . Computer-readable program code logic when executing to perform, for example, the following: obtaining information from servers on a calendar network, information relating to a definition of the timing network; and using the information by the servers to ensure the network's timing servers are adhering to its configuration.

Methods and systems of one or more aspects of the present invention are also described and claimed here.

Additional advantages and features are realized through techniques of the present invention. Other embodiments and aspects of the invention are described in detail here and are considered a part of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more aspects of the present invention are particularly highlighted and distinctly claimed as examples in the claims upon completion of the specification. The precedents and other objects, features and advantages of the invention result from the following detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1A illustrates an example of a coordinated calendar mixed network to incorporate one or more aspects of the present invention,

-3 / 64Fig. 1B illustrates an example of an STP-only network to incorporate one or more aspects of the present invention;

Fig. 2 shows an example of a stratum-1 configuration information block, in accordance with an aspect of the present invention;

Fig. 3 illustrates an example of a new block of configuration information stratum 1, in accordance with an aspect of the present invention

Fig. 4 is a pictorial representation of a null configuration, according to an aspect of the present invention;

Fig. 5 is a pictorial representation of a single server layer 1 configuration, in accordance with an aspect of the present invention;

Fig. 6 describes a personification of the logic associated with creating a single server layer 1 configuration, according to an aspect of the present invention;

Fig. 7 is a pictorial representation of a dual server layer 1 configuration, according to an aspect of the present invention;

Fig. 8 depicts a personification of the logic associated with creating a dual server configuration, according to an aspect of the present invention;

Fig. 9 is a pictorial representation of a triad configuration, by SCOÍUU UiJiii uiii aõpaUiU tia iiivcíiÇaU pi UoUí te

Fig. 10 depicts a personification of the logic associated with the creation of a triad configuration, according to an aspect of the present invention;

Fig. 11A depicts an order block embodying a modification of stratum 1 according to an aspect of the present invention;

Fig. 11B depicts a response block embodying a modification of stratum 1 according to an aspect of the present invention;

-4 / 64Fig. 12A depicts a personification of a notification change order block configuration, in accordance with an aspect of the present invention;

Fig. 12B depicts a personification of a notification change response block configuration, in accordance with an aspect of the present invention;

Fig. 13A depicts one embodies a modification request block

CTN ID, according to an aspect of the present invention

Fig. 13B depicts a personification of a CTN ID modification response block, in accordance with an aspect of the present invention;

Fig. 14A depicts a personification of a CTN reading parameters 10 request block, in accordance with an aspect of the present invention;

Fig. 14B depicts a personification of a CTN reading block response parameters, in accordance with an aspect of the present invention;

Fig. 15 depicts a personification of the logic associated with performing the recovery of an active layer 1 failure server, according to an aspect of the present invention;

Fig. 16 depicts a personification of the logic associated with the retrieval procedure of a dual server stratum 1 configuration, in accordance with an aspect of the present invention

Fig. 17 depicts a personification of the logic associated with the retrieval procedure a triad configuration stratum 1, in accordance with an aspect of the present invention;

Fig. 18A depicts a personification of the logic associated with assisted console retrieval, in accordance with an aspect of the present invention;

Fig. 18B describes a configuration resulting from console assisted retrieval, in accordance with an aspect of the present invention;

-5 / 64Fig. 19A depicts a personification of the logic associated with performing triad recovery, in accordance with an aspect of the present invention;

Fig. 19B is a pictorial representation of a layer 1 acquisition after active layer 1 checkstop, according to an aspect of the present invention

Fig. 19C is a pictorial representation of a layer 1 server acquisition after the loss of links to the active layer 1, according to an aspect of the present invention;

Fig. 19D is a pictorial representation of non-unique stratum 1 link acquisition, according to an aspect of the present invention;

Fig. 20 depicts a personification of the logic associated with making an active layer 1 acquisition, according to an aspect of the present invention;

Fig. 21 depicts a personification of the logic associated with making an active layer 1 delivery, in accordance with an aspect of the present invention;

Fig. 22A depicts a personification of a server state request block request, in accordance with an aspect of the present invention;

Fig. 22B depicts a personification of a request server state response block, in accordance with an aspect of the present invention;

Fig. 23A depicts a personification of a server state request block recording, in accordance with an aspect of the present invention;

Fig. 23B depicts a personification of a recording server response block state, in accordance with an aspect of the present invention;

Fig. 24 depicts one embodies a processing environment to incorporate and use one or more aspects of the present invention;

Fig. 25 depicts even more details about the memory of Fig. 24, in accordance with an aspect of the present invention; and

-6 / 64Fig. 26 illustrates an example of a computer program product to incorporate one or more aspects of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In accordance with an aspect of the present invention, a facility is provided to define a layer-1 configuration for a calendar network that includes a single layer 1 usable active server to ensure that the servers on the network use the same primary reference time as their clocks. Thus, the servers on the network are synchronizing the same root reference time and synchronization accuracy is not dependent on the quality of an external time source or the existence of an external time source on the stratum-1 server.

In another aspect of the present invention, the layer-1 configuration is maintained in a layer of layer-1 configuration information that is provided to the network servers, along with other information, which is used to ensure the integrity of the servers. . Since each server on the network is aware of the identity of server stratum 1, servers that indicate that they are synchronized to another server stratum 1 are not allowed to join the network.

In yet another aspect of the present invention, recovery procedures are provided to deal with a failure of the active server layer 1 of the network.

Although several networks can be configured to include a tier 1 server, such a network is a coordinated timing network (CTN). In a coordinated timing network, several different computing systems maintain time synchronization to form the coordinated timing network. Coordinate timing network systems employ a message based protocol, referred to as a Server Time Protocol (STP), to pass timekeeping information between systems over existing, high-speed data links. This allows the time of day (TOD) clocks on each system to be synchronized with the accuracy required in

-7 / 64 today’s high-end computing systems. Since the protocol makes use of technology within a computer system, precision synchronization scales as technology improves. A computer system that provides an STP mechanism is referred to as a time or server here.

A server defined in a CTN as a primary time server provides a primary reference time for the CTN. The server in a CTN, which determines the CST (a clock estimate (TOD) time of day for the CTN) based on information from another server, the CTN is called a secondary time server. The primary time server can obtain its time from an external time source, which provides the means to synchronize the time of day clocks on a CTN with a defined time pattern.

Servers in a CTN, which are in the synchronized state, receive a value, referred to as a stratum level, which specifies the number of servers between it and a primary time server. A primary time server operates at a stratum level of 1; Secondary time servers operate at a stratum level of 2 or higher, which increases as the number of servers in the stratum-1 increases calendar path. In general, the quality of timekeeping information decreases as stratum level increases. The server that is not synchronized is assigned a layer level of 0.

The STP facility provides the necessary procedures for transmitting, receiving and processing STP messages. STP messages are transmitted over one or more physical data links between servers. The data link that has been established between two servers is called an STP path. The STP facility provides facilities for establishing and maintaining STP paths.

STP messages include a message command and a message response. Two types of STP messages are supported. The exchange time parameters message (XTP) and the STP control message (STC). The XTP message is used to exchange the timekeeping information used to determine CST for CTN. Control messages

-8 / 64STP are used to define and modify various CTN parameters required by servers in CTN.

You can operate a CTN, for example, as one of two types of configurations: as a mixed CTN configuration or as a STP-only CTN configuration. In a mixed CTN configuration, the servers are configured to be part of an external time reference network (ETR) and an STP network. In a mixed CTN configuration, the CTN servers are configured with the same, non-null ETR network ID and a timer (for example, IBM Sysplex Timer®) provides the main time reference to CTN. At least one server in the CTN is stepping the timing signals provided by the SYSPLEX timer before synchronization can occur within the CTN. Non-backup servers for the sysplex timer are secondary time servers and achieve synchronization by exchanging STP signals.

As an example, each backup server for the SYSPLEX timer Timing signals receives the time protocol parameters and propagates the information to secondary time servers in CTN, using, for example, a CTN parameter update procedure. An example of this process is described in US Serial No. 11 / 468,352, “Coordinates Timing Network Configuration parameter Update internal,” Carlson et al., Presented on August 30, 2006, the right that remain is incorporated here by reference in its entirety.

An example of a mixed CTN 100 configuration is described with reference to Fig. 1. Mixed CTN 100 configuration includes, for example, a server one (102) tied to a local area network (104), a B Server (106) tied to the local area network (104) and a Server C (108) coupled to a local network (110). Each server is, for example, a complex processing center based on az / architecture © offered by International Business Machines Corporation. Z ® architecture is a registered trademark of International Business Machines Corporation, Armonk, New York, USA. An embodiment of z / architecture ® is described in z / architecture, principles of operation, ”IBM publication no. SA22-7832-04, September 2005, are hereby incorporated by reference in their entirety.

-9 / 64Each local area net ^ ork is connected to a console 120 used to provide time synchronization within the network. In addition, local network 104 and local area network 110 are linked to each other via a wide area network 112.

Servers A and B are tied to an external time reference network 114 and servers B and C are configured to integrate a network of STP 116. Server B is at a tier 1 level and server C is at a tier 2 level. STP 118 links are used to track the STP installation of server B with the STP Server c facility.

In an STN-only CTN, the CTN servers are configured to be part of an STP network and none are configured to be part of an ETR network. An example of a STP 150 only network is described with reference to Fig. 1. In this example, server one (152) and server B (154) are tied to a LAN (156) and server C (158) is tied to a LAN (160). Each of the servers includes an STP 162 mechanism and each installation is coupled to each other via one or more STP 164 links.

In addition, LAN 156 is tied to a console 170 and LAN 160 is tied to a console 172. Console 170 is even more tied to an external time source (ETS) 174, such as a dial out phone time server ( for example, acts; NIST automated computer timing service). In this network, there is no ETR network. Server B has a stratum level of 1, and servers A and C have a stratum of 2.

The server that is acting as layer 1 server active on the network, as an STP-only network, is specified as part of a layer 1 configuration defined for the network. The stratum-1 configuration is maintained on each server in the network and provides information related to the network configuration, including, for example, the type of configuration defined for the network. The network can be configured as one of several types, including, for example;

a) null configuration - in a null configuration, a layer 1 server is not identified. The server remains

-10 / 64 not synchronized, until it assigns to a server that has a non-null layer 1 configuration. Stratum 1 coniiguity on a server that is at stratum level 0 is equal to the null configuration when, for example, it is not attached to any other server and the only CEC-CTN indicator in a stratum configuration information block -1, described below, is zero.

b) the only Server definition - in a single server definition, layer 1 configuration defines a single layer 1 primary server that acts as a layer 1 active server for CTN. The loss of the primary stratum 1 server results in the synchronized time loss in the CTN until a new stratum-1 configuration is specified on the console.

A single tier 1 server configuration may also include an indication that the specified tier-1 server is the only server (for example, electronic complex computing (CEC) or CPC) at CTN and that no other or additional servers will be part of the CTN. In this case, the CTN is called a single CEC CTN. When a stratum-1 configuration indicates that it is a single CEC CTN, the configuration is a valid stratum-1 configuration for the initialized state of the server after a power over reset. When a single server layer 1 configuration does not specify that it is a single CEC CTN, the configuration is not a valid layer 1 configuration for the initialized state of the server after a power over reset and the layer 1 configuration is defined in null configuration.

c) dual server configuration - in a dual server configuration, the configuration includes a primary stratum-1 server and an alternate stratum-1 server. The use of a dual server configuration provides a mechanism for an alternate server to assume the role of stratum-1 active server for CTN. The tier 1 alternate server, when configured with the

-11 / 64 and the same tactics for other servers, the CTN, which the primary tier 1 server, can assume as the active tier-1 without interruption for the CTN synchronization feature. The tier 1 server (primary or alternate) that is acting as the tier 1 active server for a CTN is indicated in the tier 1 configuration information block maintained on each server in the CTN, as described below. The tier-1 server that is not the tier 1 active server is defined as the inactive tier 1 server.

The inactive tier 1 server in a dual server configuration resumes the role of the tier-1 active server when it detects an active tier 1 failure. An active layer 1 failure is detected in a dual server configuration when one of the following occurs: ·

A console assisted recovery procedure is performed and indicates that an active stratum-1 failure has occurred, or

A stratum 1 system check signal is recognized.

The inactive tier 1 server in a dual server configuration performs assisted console recovery when the inactive tier 1 server loses the attachment to the active tier-1 server.

d) Triad configuration - in a triad configuration, layer 1 configuration includes a primary layer 1 server, an alternate layer 1 server, and an arbitrator server. The definition of a triad configuration provides a mechanism for an alternate server to be able to assume the role of tier-1 active server for CTN, as defined for a dual server configuration. In addition, the definition of an arbitrator server, when configured with connectivity to primary stratum 1 and alternate stratum 1 servers, provides a mechanism for inactive stratum-1 and arbitrator servers to communicate with each other to be able

-12 / 64determine that a failure of stratum-1 active server has occurred and that inactive stratum-1 should assume as the active stratum 1 server.

Inactive layer 1 server in a triad configuration assumes the role of layer 1 active when it recognizes a failure layer 1 active. The inactive layer 1 server recognizes an active layer 1 failure when any of the following occurs:

• a triad recovery procedure is performed and indicates that a stratum 1 active failure has occurred.

· An assisted console recovery procedure is performed and indicates that an active layer 1 failure has occurred.

The inactive tier 1 server performs the triad recovery procedure when the following conditions occur:

• The inactive tier 1 server loses the attachment to the active tier 1 server and has an attachment for the referee.

• The inactive tier 1 server recognizes a tier 1 active communication timeout and has an attachment for the referee.

The inactive layer 1 server performs assisted console recovery when the inactive layer 1 server loses the attachment to the active layer 1 server and does not accompany the referee.

The inactive layer 1 server performs the process of acquiring 25 active layer 1 to assume the role! stratum 1 server active for CTN.

The tier 1 active server in a triad configuration gives the role of the tier-1 active server when it detects that it has lost the attachment to the inactive tier 1 server and the referee server. The tier 1 active server

-13 / 64 performs a tier-1 active delivery procedure to abandon the role of tier-1 active server for CTN.

For example, layer-1 configuration information is kept in a control block, referred to as layer-1 configuration information block (SCIB), which is stored on or accessible to each server on the network. The SCIB is used to identify the layer-1 configuration for a network.

One embodies a block of configuration information of layer 1 200 is described with reference to Fig. 2. Stratum-1 block of configuration information 200 includes, for example, the following fields:

a) single layer 1 node descriptor 202: this field is valid when a single server, dual server or triad definition has been specified in the configuration type field of the configuration information block, described below and when valid, includes the node descriptor of primary descriptor stratum 1 node.

b) alternate stratum 1 node descriptor 204: this field is valid when a dual server or triad definition has been specified in the configuration type field and when valid, includes the node descriptor of the stratum-1 alternate server node descriptor.

c) Referee node descriptor 206: this field is valid when a triad definition has been specified in the configuration type field and includes the node descriptor of the referee server node descriptor.

d) Stratum-1 configuration timestamp: this field includes a timestamp indicating the time at which stratum-1 configuration information in this block became current on the server.

-14 / 64e) type, configuration (CType) 210: this field specifies the type of configuration of layer-1, as defined below:

• null definition - none of the node defectors are valid.

• The definition of single server - only the defector of primary stratum 1 node is valid.

• Definition of dual server: defectors of the main layer 1 layer 1 and alternative defectors are valid.

• Definition of triad: The primary stratum-1, alternative stratum-1 and deserter node arbitrators are valid.

f) active layer 1 (A) 212: this field is valid when a dual server or triad definition has been specified and indicates whether the primary server layer 1 or the alternate server layer 1 is layer 1 active server.

g) CEC single CTN (X) 214: this field is valid when the configuration type specifies a single server definition and when one, for example, indicates the CTN is a single CEC CTN. When the field is, for example, zero, the CTN is not a single CTN. CEC

h) recovery configuration (R) 216: this field indicates whether the layer 1 configuration described by this block is the result of a layer 1 recovery action or a console command.

i) stratum 1 maximum short term distort rate change 218: this field includes a value that specifies the maximum possible change in the skew rate of the physical Oscillator on server 1 stratum that can occur during any specified period (for

-15 / 64example, 60 seconds). This field is used to form a value that is in the same format as the base rate of direction.

On machines that are not capable of executing the switching oscillator dynamic, the value is equal to the maximum frequency drift of stratum-1 oscillator that can occur during a specified period (for example, 60 seconds). On machines that are capable of executing the switching Oscillator dynamic, the value is defined as the maximum skew tolerance range specified for the Oscillator. For example, on a machine that supports dynamic Oscillator, alternating with skew tolerance Oscillator specified at 1-2 ppm nominal frequency, the value is set to the equivalent of 4 ppm. A dynamic oscillator switch occurs when the physical oscillator used to drive the TOD clock system is switched from one oscillator to another.

In addition to the control block above, another control block, called the new stratum-1 configuration information block (NSCIB), can be used to specify a new stratum-1 configuration for CTN. In addition, it can be used to specify an update to the CTN ID to occur simultaneously with the stratum-1 configuration change.

For example, the NSCIB on a server is significant when the server is configured to be part of a STP-only CTN configuration or if the migration of STP bit in the NSCIB is equal to one.

One embodies a new layer of configuration information of layer 1 300 is described with reference to Fig. 3. New block of information of configuration of layer 1 300 includes, for example, the following fields:

a) single layer 1 node descriptor 302: this field is valid when a single, double or triad definition server server has been specified in the configuration type field and includes the node descriptor of new primary layer 1 node descriptor.

b) alternating stratum 1 node descriptor 304: this field is valid when a dual server or triad definition has been

-16 / 64 specified in the configuration type field and includes the node descriptor of the new stratum-1 alternative node descriptor.

c) Referee node descriptor 306: this field is valid when a triad definition has been specified in the configuration type field and includes the node descriptor of the new referee node descriptor.

d) stratum 1 Update Time 308 configuration: when the server is configured to be part of a single STP CTN, this field includes a timestamp that indicates when the values ​​in this block should become current for CTN.

e) type of configuration (CType) 310: this field specifies the type of configuration of layer-1, as defined below:

• null definition - none of the node defectors are valid.

• The single server definition - only the primary layer 1 node descriptor is valid.

• Definition of dual server: defectors of the main layer 1 layer 1 and alternative defectors are valid.

• Definition of triad: The primary stratum-1, alternative stratum-1 and deserter node arbitrators are valid.

f) activate layer 1 (A) 312: this field is valid when a dual server or triad definition has been specified and indicates whether the primary server layer 1 or the alternate server layer 1 is layer 1 active server.

g) change the CTN ID (C) 314: when the server is configured to be part of a single STP CTN, this field indicates whether a change in the CTN ID is being requested and the

-17 / 64 CTN identification is valid. The change occurs in the layer-1 configuration update time.

CTN identification is a value that is used to identify a CTN. The CTN ID includes, for example, an STP network ID and an ETR network number. The STP network ID identifies the STP network, if any, that is configured for the server. The ETR network number identifies the ETR network number, if any, that is configured for this server.

h) STP (S) 316 migration configuration: this field is significant when, for example, the server is not configured as a STN-only CTN. The field indicates whether a STP-only migration layer 1 configuration has been defined for the server. When the field is, for example, one, the NSCIB includes the stratum-1 configuration to become current when the CTN ID on the server is changed to an STP-only configuration. When the field is, for example, zero, a STP migration layer 1 setting is not defined for the server.

i) single CEC CTN (X) 318: this field is valid when the configuration type specifies a single server definition and when one, for example, indicates the CTN is a single CEC CTN. When the field is, for example, zero, the CTN is not a single CTN. CEC

j) recovery configuration (R) 320: this field indicates whether the layer 1 configuration described by this block is the result of a layer 1 recovery action or a console command.

k) stratum 1 maximum short term distort rate change 322: this field includes a value that specifies the maximum possible change in the skew rate of the physical Oscillator on the stratum 1 server

-18 / 64new that may occur during any specified period (for example, 60 seconds).

I) new CTN ID 320: this field is valid when the CTN ID change indicator specifies a change order CTN ID and a valid CTN ID. This field specifies the new CTN ID.

If the new block of layer 1 configuration information should not be used to specify an update to the CTN ID, then the block cannot include the change bit of the CTN ID or the new CTN ID, for example.

The stratum-1 configuration is initialized on a server to a zero configuration, the initial power relatively to the machine. An example of a null configuration is shown in Fig. 4. As shown, a null configuration 400 includes a plurality of servers 402, which are linked to each other via one or more STP 404 links. In this example, the stratum level of each server is equal to zero, and thus, there is no active layer 1 server. However, the CTN ID is set to a specific value, which, in this example, is defined using a local modify CTN command console ID, as described below.

A CTN, which has a null stratum 1 configuration, cannot be synchronized, since a stratum-1 has not been specified and there is no reference time for the CTN. The layer-1 configuration for a CTN can be set back to a null configuration from a non-null configuration using a command, such as the layer 1 modification configuration command, described below.

From a null configuration, it is possible to create a single layer-1 server. A single tier 1 server configuration specifies a single tier 1 server and no alternate tier 1 server or referee. An example of a single server layer 1 configuration is shown in Fig.

5. As shown, a single server 500 layer 1 configuration includes a

-19 / 64plurality of servers 502 tied to each other via one or more links from STP 504, and one of the servers, for example, server A, is selected as the primary stratum 1 active server. Thus, server A has an indication of the primary-S1 and its stratum level is equal to one. Note that the other servers stratum values ​​greater than, like two or three.

A personification of the logic associated with creating a single server layer 1 configuration is described with reference to Fig. 6. Initially, the console issues a command, such as the command modification layer 1 configuration, to server one specifying a configuration. tier 1 single server with Server A as the primary tier 1 server, 600 STEP.

Subsequently, Server A indicates that the new configuration of the current layer1, STEP 602. An example, Server A questions the configuration change notification command for the console to give this indication.

Subsequently, the other servers in the network recognize the existence of a clock source and obtain the current stratum-1 configuration and time control parameters for CTN, 604 STEP. An example, this is accomplished by the servers to issue a STP control message reading CTN parameters to the clock source to obtain the current stratum-1 configuration and time control parameters for the CTN.

In addition, the servers issue a change machine configuration check, in an example, to indicate the new setting stratum 1, STEP 606. The servers also indicate a change in Timing status (usable source clock, synchronized), for example, issue an external alert timing interrupt, 608 STEP. This completes processing associated with creating a single server layer 1 configuration from a null configuration.

In addition to the above, a dual server configuration can be created from an existing non-null configuration. A dual tier 1 server configuration specifies a primary and alternate tier 1 server,

-20 / 64one of which can act as a strat-1 active server for CTN. The server that is acting as the tier-1 server is specified by the console at the time the tier-1 configuration is created and can be changed at any time via the console.

An example of a dual server tier 1 configuration is shown in Fig. 7. As shown, server one (700) is indicated as the primary and has a tier level of 1. Server C (702) is indicated as alternate and has a stratum level of 2. Servers B (704) and D (706) have a stratum level of two and Server E (708) has a stratum level of 3.

A personification of the logic associated with creating a dual server configuration is described with reference to Fig. 8. Initially, a dual layer server configuration is specified that has Server A as its primary and active and C Server as its alternate, 800 STEP. For example, this is accomplished by the console issuing a layer 1 configuration command modification to server A.

Subsequently, a determination is made as to whether the power change bit in the modification layer 1 command is 0, 802 inquiry. If it is 0, Server A verifies that it is directly attached to server C, STEP 804. For example, this attachment is verified by exchanging a message with Server C. If the check indicates that Server A directly accompanies Server C, inquiry 806, then Server A schedules a stratum 1 configuration update in CTN, 808 STEP and the update will occur 809 STEP. In addition, server A issues a command configuration change notification, for example, to the console when the new layer 1 configuration becomes current, step 810. The network servers also issue a change machine configuration check in response to the new layer 1 configuration becoming current, 812 STEP.

Returning to the 802 survey, if the change force bit is set to 1, then processing continues with 808 STEP, in which server schedules A stratum 1 configuration update in CTN.

-21 / 64Referring to inquiry 806, if Server A Server C is not attached, then the command is rejected, 814 STEP and transformation complete.

In addition to creating a dual configuration from an existing non-null configuration, a triad configuration can also be created from an existing non-null configuration. A stratum 1 triad configuration specifies a primary stratum-1 server, an alternate stratum1 server, and an arbiter server. The specified primary or alternate can act as a stratum-1 active server for CTN. The server that is to act as layer 1 server specified by the console at the time the layer-1 configuration is created can be changed at any time by the console. The referee server is used to help determine when the stratum 1 active server is no longer part of the CTN.

An example of a triad configuration is shown in Fig.

9. As shown, server one (900) is the primary server of layer-1 and has a layer level of one. In addition, C Server (902) is the alternate tier-1 server and has a tier 2 level and B Server (904) is the arbiter and also has a tier level of 2. In addition, Server D (906) has a stratum level of 2 and Server E (908) has a stratum level of 3.

A personification of the logic associated with the creation of a triad configuration is described with reference to Fig. 10. Initially, the console issues, for example, a layer configuration 1 modification command to the server one specifying a triad configuration, in that Server A is the primary tier 1 active server, Server C is the tier-1 alternate server and B Server is the referee, 1000 STEP.

Subsequently, a determination is made as to whether the power change bit in the layer 1 modification configuration command is set to 0, 1002 of inquiry. If it is set to 0, Server A checks that servers C and B, 1004 STEP, are directly attached. If Server A attached to servers and B, survey 1006, then Server A schedules a stratum 1 configuration update in CTN, STEP 1008 and the update will occur

-22 / 641009 STEP. Server A also issues a configuration change notification command to the console, in response to the new layer 1 configuration becoming current, 1010 STEP. Subsequently, the servers issue a configuration change machine check when the new stratum configuration

1 stays current, step 1012.

Returning to survey 1002, if the change bit is equal to one, then connectivity verification is not performed and processing continues with 1008 STEP, in which server schedules A layer 1 configuration update in CTN.

Also, if the connectivity check fails, inquiry 1006, then the command is rejected, 1014 and processing is completed.

As described above, when creating a non-null configuration, several commands are used. Such a command is a layer 1 modification configuration command, which is used to specify a change from layer-1 configuration to CTN. The command request includes a new block of layer-1 configuration information that specifies how the layer-1 configuration should be modified.

An embodiment of the modification block of command request for layer 1 1100 is described with reference to Fig. 11 A. An example, the modification layer of command command for modification of layer 1 includes the following fields:

a) 1102 of the length field: this field indicates the size of the requested block.

b) the code 1104 command: this field specifies the modification layer-1 configuration command.

c) number of transactions for the 1106 command: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

-23 / 64d) CTN ID 1108: this field includes the CTN ID of the CTN directed to the command.

e) confirm strength (F) 1110: this field indicates whether the configuration check is to be performed for the command.

f) stratum 1 Configuration Information block 1112 new: this field includes the new stratum-1 configuration information block for CTN.

A personification of a response block of the modification layer 1 command is described with reference to Fig. 11B. Modifying layer 1 configuration response block 1150 includes, for example, the following fields:

a) 1152 length: this field includes the size of the command response block.

b) response code 1154: this field includes the response code of the command.

c) number of transactions of the 1156 command: this field includes the value provided in the command numeric transaction field of the command request block.

In operation, when the command Specifies a new tier-1 active server for CTN, the command is issued to the server designated as tier 1 active server in the NSCIB. If it is not sent to the server, a global command rejection response code will be resumed.

The new active layer 1 server asynchronously issues a configuration change notification command after the update takes effect within the CTN. When the command is issued to a server in a mixed CTN, the STP migration field (S) in the NSCIB is set to one. This field indicates that the stratum-1 configuration is to take effect

-24 / 64when the CTN configuration changes from a Mixed CTN to an STP only configuration.

command request block includes a field to indicate whether the configuration check should be performed for the command. The change of force field is defined as, for example, 1 to indicate that the command must be executed without configuration verification. The change of force field is set to, for example, 0 to indicate that the following configuration checks are being performed before the command is accepted:

If a non-null configuration is specified, check that the receiving server is not a tier 0 server. The force change field is set to 1 to define a tier 0 server for the active tier-1 server.

If a dual configuration is specified, the receiving server checks for the following:

If the receiving server is designated as the tier-1 primary server, it ensures that it accompanies the tier-1 alternate server.

If the receiving server is designated as the tier-1 alternate server, it ensures that it accompanies the tier-1 primary server.

If a triad configuration is specified, the receiving server checks for the following:

If the receiving server is designated as the tier-1 primary server, it ensures that it is connected to the tier-1 alternate server and referee server.

If the receiving server is designated as the tier-1 alternate server, it ensures that it is connected to the tier-1 primary server and referee server.

-25 / 64If the verification checks fails, the command is not accepted and a response code is reported.

Another command mentioned above is the configuration of changing the notification command (CCN). The change command notification setting is used to notify the console of certain CTN configuration changes. The command is issued by the network servers after the CTN takes effect configuration. The command is issued for the following configuration parameter changes, as examples: configuration change layer 1; configuration change of stratum-1 and CTN ID change; and / or changing the CTN ID.

Configuration changes occur as a result of a modification layer-1 configuration command, a global modification CTN ID command, or as a result of CTN recovery actions, which cause a change in the layer-1 active server for CTN.

An example of a 1200 command request block for the change command notification setting is described with reference to Fig. 12. In a personification, the 1200 command request block includes the following:

a) 1202 length: this field includes the size of the command block.

b) the code 1204 command: this field includes a specification of the configuration change notification command.

c) number of transactions for the 1206 command: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

d) CTN ID 1208: this field includes the CTN ID of the server sending the command.

-26 / 64e) change code: this field includes a code that specifies the configuration changes being reported. This field indicates, for example: configuration change • layer 1: The layer 1 configuration has changed as indicated by the current layer-1 configuration block.

• Change of layer 1 configuration and change of CTN ID: The layer 1 configuration and CTN identification has changed as indicated by the current layer-1 configuration block and the CTN ID field.

• Change CTN ID: The CTN ID has been changed as indicated by the CTN ID field.

f) code to reason: this field includes a code that specifies the reason for a change in stratum-1 configuration being reported. This field is valid when a stratum-1 configuration change is being indicated in the change code and indicates one of the following, as examples:

• modify layer 1 configuration: The layer 1 configuration change is the result of a modify layer 1 configuration command • Recovery: The layer 1 configuration change results from an action to recover STP installations.

g) current layer 1 Configuration Information block: this field includes the current layer-1 configuration information block for the server.

-27 / 64A personification of a 1250 command response block for the change command notification setting is described with reference to Fig. 12.oB. For example, the response block for command 1250 includes the following:

a) 1252 length: this field specifies a response block length for the command.

b) response code 1254: this field includes the response code of the command.

c) number of transactions of the 1256 command: this field includes the value provided in the command numeric transaction field of the command request block.

Another command that can be executed is to modify the CTN ID command, which is used to perform a local or global CTN ID change. The command can be used to modify the CTN STP network ID component, the ETR network ID component, or both components of the

CTN. Validity indicators in the order block indicate which components of the CTN ID to modify. The global command parameter in the request block specifies whether the command is a global command or a local command.

An example of a command request block 1300 for modifying CTN command ID is described with reference to Fig. 13A. Modify

CTN order ID block 1300 includes, for example:

a) 1302 length: this field includes a control block length.

b) command code 1304: this field specifies the CTN ID of the modification command.

c) number of transactions for the command 1306: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

-28 / 64d) CTN ID 1307: this field, when valid, includes the CTN ID of the CTN directed to the command. The CTN ID is valid, when the global update indicator of the CTN is, for example, 1 and corresponds to the current CTN identification on the receiving server; otherwise, a CTN ID mismatch error is recognized. When the global CTN update indicator is, for example, 0, this field is not valid and is ignored.

e) global CTN Update (G) 1308: this field indicates whether the command is a global or local update. When the command is a local update, it is performed only on the receiving server. When the command is a global command, the command is issued to the active stratum-1 server.

f) new valid STP Network ID (VA) 1310: this field indicates whether the new STP network ID field is valid. When not valid, the STP network ID portion of the CTN ID is not modified by the command.

g) new valid ETR Network ID (EV) 1312: this field indicates whether the new ETR network ID field is valid. When not valid, the ETR network ID portion of the CTN ID is not modified by the command.

h) new STP 1314 network ID: when SV the indicator is valid, this field includes the new STP network identification.

i) new ETR 1316 network ID: when EV the indicator is valid, this field includes the new ETR network identification.

j) ETR port 0 manual port State 1318: when EV the indicator is valid, this field includes a manual port status code that specifies the desired state of ETR port 0.

-29 / 64k) ETR Port 1 manual port State 1320: when EV the indicator is valid, this field includes the manual port status code that specifies the desired state of the ETR port

1.

A personification of a 1350 command response block for a CTN command ID modification is described with reference to Fig. 13B. An example, modifying the CTN ID of the 1350 command response block includes, for example, the following: a) 1352 lengths: this field includes a value specifying a command response block length.

b) response code 1354: this field includes the response code of the command.

c) number of transactions of the 1356 command: this field includes the value provided in the command numeric transaction field of the command request block.

An example, when the CTN modification ID is issued as a local CTN update, the STP permanent facility performs the update immediately, and a configuration change notification command is not issued to the console. In addition, when the CTN modification ID is issued as a global CTN update, stratum 1 active server issues the configuration change notification command to the console when the update becomes current.

When the CTN modification ID is issued as a global CTN update, the STP facility performs the CTN parameter update procedure to schedule a modification of CTN operation by the CTN servers. The scheduled update time is defined as a value that ensures that the CTN servers receive the update information before the scheduled update time. A specified response code indicates that the operation was successfully scheduled at CTN.

When the update is scheduled on a server, the server stores the scheduled parameter update information for

-30 / 64 console disk storage. In addition, when the parameter update is current on a server, the server stores the updated CTN parameters for console disk storage.

For example, a command, referred to as a save CTN command parameter, is issued by the server to store the information. The command includes a request block, having, for example, length and command code fields, as well as a command transaction number, a CIIB; an STP enabled installation indicator that indicates whether the STP installation is enabled, a local clock source indicator that specifies whether the server has been designated as the local clock server; an active Oscillator indicator that identifies the Oscillator that is active at the time of the rescue command; a SCIB; and an NCIIB; a layer-1 based on the director fee that includes a base orientation fee for the server when it is functioning as a layer 1 server an NSCIB; a PCSIB; a TCPIB; an LSOIB; a save timestamp that indicates the time the save command was issued; an Oscillator identifier 0; a computed oscillator distorting 0; an identifier oscillator 1; and a field of 1 computed Oscillator skew. Many of these fields are described below with reference to Fig. 14B. A command response block for the command includes, for example, a length, response code and command transaction number.

A local CTN ID change occurs on a server as a result of the CTN ID modification console command issued as a local command. The server that receives the CTN ID command console modification, an example, immediately (in an example) makes a specified change to the CTN ID on the server and places all STP paths established on the uninitialized state server and then establishes the Initiative to perform initialization on STP lengths. A configuration change machine check condition is generated when the CTN ID change occurs.

A global CTN ID update takes place on a server at the time of the CTN ID update specified in the new CTN ID block. The server

-31 / 64 changes your CTN ID to the specified update time. Following the change, the server does not recognize the CTN ID incompatibility errors that have occurred as a result of the incompatibility between the new CTN ID and the old CTN ID values ​​for a period equal to the synchronization check threshold. CTN ID mismatch errors that occur as a result of the different incompatibility between the new CTN ID and the old CTN ID values ​​are not ignored during this period. A configuration change machine check condition is generated when the CTN ID change occurs.

The stratum-1 active server issues a configuration change command console notification after making a CTN ID update that occurs as a result of the global CTN ID update.

In addition to the commands described above, the STP console interface includes commands to read calendar information and the STP configuration of a server. The information provided in the read commands is made available to use via console presents. An example of a command request block 1400 for a readable CTN parameter command is described with reference to Fig. 14A. An example, reading order block from CTN parameter command 1400 includes, for example:

a) 1402 length: this field includes a value specifying a command block length.

b) the code 1404 command: this field includes a value specifying the CTN read parameter command.

c) number of transactions for the command 1406: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

A response block of command 1450 for the CTN parameter command reading is described with reference to Fig. 14B. For example, response block 1450 includes the following:

-32 / 64a) 1452 length: this field is used to indicate a response block length for the command.

b) response code 1454: this field includes the response code of the command.

c) number of transactions of the command 1456: this field includes the value provided in the command numeric transaction field of the command request block.

d) CTN ID Information block 1458: this field includes the CTN ID information block (CIIB) for the server.

In an impersonation, the CTN ID information block includes the CTN ID for the server and codes specifying the ETR port state 0 and 1, in a non-null ETR network.

e) maximum STP version 1460: this field includes a value that indicates the maximum STP version number supported by the server.

f) active STP version 1462: this field includes a value that indicates the version number of STP that is already active on the server.

g) maximum stratum level time 1464: this field includes a value that specifies the maximum stratum level that a server can be set and the state synchronized. A server with a stratum level higher than the maximum time stratum level is the non-synchronized calendar state and the non-usable clock source state.

h) 1466 maximum stratum level: this field includes a value that specifies the maximum stratum level that can be defined for any server, the CTN.

-33 / 64i) local clock source (L) 1468; this field specifies whether the server has been designated as a local clock server.

j) STP (C) 1470 clock source state: this field specifies the server clock source state.

k) Oscillator active (A) 1472: this field identifies the Oscillator is considered active by the installation of STP.

l) timing Mode (TDM) 1474: this field specifies the server's calendar mode.

m) STP timing status (TST) 1476: this field specifies the time status on the server.

n) CTN type (CTNT) 1478: this field includes a code that specifies the type of calendar network that is configured on the server. Example types include: · no defined CTN: the server is not configured to be attached to a STP CTN only Timing network.

·: The server is configured for attachment to a CTN, which includes only one STP network.

• Mixed with the Timing network: the server is configured for attachment to a CTN, which includes an STP network and an ETR network.

o) layer 1480: this field includes a value indicating the server's layer level.

p) new CTN ID Information block (NCIIB) 1482: this field includes the new CIIB for the server. The new CTN ID update time is stored in UTC (universal time, coordinated) format.

-34 / 64An example, the new CTN ID information block includes a new CTN ID; ETR port 0 manual port Status; ETR port 1 manual door State; and a new CTN ID updates the time, which is, for example, a time stamp indicating the time when the new CTN ID becomes current.

q) current layer 1 Configuration Information block (SCIB) 1484: this field includes the current layer-1 configuration block for the server.

r) new layer 1 Configuration Information block (NSCIB) 1486: this field includes the new layer of configuration layer 1 for the server.

s) PRT (primary reference time) correction director information block (PCSIB) 1488: this field includes the PCSIB for the server.

An example, the correction guidance information PRT Block includes the following:

1. PRT correction rate director Start Time: this field includes a timestamp indicating the time that PRT-direction correction is to be started.

2. The PRT source identifier: this field contains the main reference time source identifier.

3. Scatter of the console: this field includes a scatter of the provided console.

4. Scatter from UTC: this field includes a scatter from UTC provided.

5. Offset of the PRT: this field includes an offset of the reference time provided.

-35 / 646. PRT timestamp: this field includes a timestamp that corresponds to a PRT timestamp provided.

t) time zone control parameter information block (TCPIB) 1490: this field includes the TCPIB for the server. The new TZIB update time and new DST offset update time are converted to UTC time stamp format.

For example, the time zone control parameter information block includes, for example, the following:

1. Local Active time code: this field includes a value that identifies whether a local time setting is in effect for CTN and if so, how it is obtained. Examples include:

• at the specified local time. The time zone offset and the DST offset are both zero.

• ATZIB Valid with automatic updates - ATZIB is valid and specifies the local time settings for CTN. The offset of active DST, new DST offset and new update time fields DSTO and TCPIB are valid and are defined based on the DST-active and DST algorithms in ATZIB. The TTO field is not valid.

• ATZIB Valid without automatic updates - ATZIB is valid and specifies the travel time zone for CTN. Any DST-na and DST-off algorithms specified in ATZIB are not used. The asset-DST offset, new DST offset and new DSTO update time fields are valid. The set command for the DST offset console is used to modify the new DSTO update time

-36 / 64e to specify whether local time should be in standard time or DST, when the update becomes current. The TTO field is not valid.

• Valid TTO field - the TTO field is valid and specifies the local time offset from the CTN and includes the time zone offset and any summer saving time offset. ATZIB, the active DST offset, the new DST offset and the new DSTO update time fields are not valid.

2. New local time code: this field includes a value that identifies whether a new TZIB is pending for CTN. Examples include:

• at the new local time specified.

• Time fields are valid and specify the new time setting for the CTN of the valid NTZIB update with automatic updates - the NTZIB and NTZIB. The new TZIB becomes current at the time of the new TZIB update. The active DST offset, new DST offset and new DSTO update times are defined based on the predicted DST- and DST-off algorithms to NTZIB when the NTZIB becomes current.

• NTZIB valid without automatic updates - the NTZIB and NTZIB update time fields are valid and specify the time zone and DST offsets that are becoming current at the time of the new TZIB update. The DST- and DST-off algorithms specified in the TZIB are not used.

-37 / 643. The new TZIB DST (D): this field is valid when the new local time code is equal to a value that represents valid TZIB-without-automatic DST-updates and indicates whether the local time for CTN should be set for daylight saving time, when the NTZIB becomes current or should be set as the standard time when the NTZIB becomes current.

4. Total time offset: this field, when valid, specifies the total time offset that is in effect in the STP installation, as a result of a DST offset and the time zone offset that is in effect on the server. The field is valid when the active time code specifies the TTO field.

5. Active time zone information block (ATZIB): this field includes the time zone information block (TZIB) currently in effect on the server.

An example, a TZIB includes:

aa) number of time zone algorithm: this field identifies the number of time zone algorithm for this movement.

bb) time zone offset: this field includes a value indicating the time difference from UTC.

cc) Summer Savings Time (DST) offset: this field includes a value indicating the DST offset is applied when the summer savings time is in effect. The date on which the DST offset value must be active for CTN and is specified by the DST-on algorithm. The date on which the DST offset to the server must be set to zero and is specified by the DST-off algorithm.

-38 / 64dd) Name standard time: this field identifies the time zone, when the DST offset is not in effect.

ee) Summer Savings Time name: this field identifies the time zone, when the DST offset is in effect.

ff) DST-On time algorithm: this field specifies the algorithm to be used for calculating the date and time when the DST offset should be applied. The offset is applied automatically when automatic DST programming is in effect for the server.

gg) DST-Off time algorithm: this field specifies the algorithm to be used for calculating the date and time when the DST offset must be removed. The offset is removed automatically when automatic DST scheduling is in effect for the server.

6. New time zone information block (NTZIB) This field, when valid, includes the time zone information block is to replace the start of ATZIB at the time specified by the NTZIB update time.

7. Active Summer Savings Time offset (DSTO): this field includes a value indicating the DST offset currently in effect on the server.

8. New Summer Savings Time Offset (NDSTO): This field includes a value that specifies the offset is to replace the start of DSTO active at the time specified by the new DSTO update timestamp.

9. Time to update the new TZIB: this field includes a timestamp that specifies the time when the new TZIB is to take effect.

-39 / 6410. New DSTO time: this field includes a timestamp that specifies the time when the new DST offset is to take effect.

u) leap second offset information block (LSOIB) 1492: this field includes the LSOIB for the server. The new LSO update time is converted to UTC time stamp format.

An example, the leap seconds offset information block, includes, for example, the following:

1. Active leap second offset provided (P): this field, when set to, for example, one, indicates that the active jump seconds offset includes a value that was provided by the operator. When the field is, for example, zero, the active jump seconds offset includes the machine initialization value and has not been set by the operator.

2. Second leap displacement asset (LSO): this field includes a value indicating the number of jump seconds that are currently in effect for the STP installation.

3. The new leap second displacement (LSO): this field includes a value indicating the number of jump seconds that are becoming active at the time specified by the LSO update time.

4. New leap time offset update (LSO Second): this field includes a timestamp that specifies the time at which the new jump seconds offset is to take effect.

v) Oscillator identifier 0 (1494): this field includes an identifier for Oscillator 0.

-40 / 64w) computed Oscillator distort 0 (COSO) of 1496: this field includes a value that specifies the computed bias in relation to the nominal frequency Oscillator 0 installed on the server.

x) Oscillator identifier 1 (1498): this field includes an identifier for Oscillator 1.

y) computed Oscillator distort 1 (COS1) 1499: this field includes a value that specifies the computed bias in relation to the nominal frequency Oscillator 1 installed on the server.

The above information is used, in one aspect of the present invention, to ensure the integrity of the time coordinated network servers. This information is propagated to the servers on the network. The network servers obtain the configuration, understand the configuration and follow the same configuration. In an impersonation, a server cannot operate for more than a predefined amount of time (for example, freewheel period) without knowing the layer-1 configuration. If a server intends to join the network, it obtains and uses this information. This information provides the CTN Status, as well as additional information.

In accordance with another aspect of the present invention, a feature is provided to configure an alternate server as part of the layer-1 configuration for a time-coordinated network such that it is able to assume that layer 1 server is active in the event of a failure in active stratum 1 server. This prevents a single point of failure for the CTN, such that servers in a CTN can maintain or gain synchronization within the timing network despite a failure in the active stratum-1 server.

As described above, a layer 1 configuration can be defined for a CTN that specifies a primary and alternate layer 1 server. Normally the primary server acts as a strat-1 active server for CTN, with the alternate acting as a backup and is designated the server

-41 / 64of stratum 1 inactive. When the inactive tier 1 server detects a failure in the tier 1 active server, it notifies the CTN (via, for example, a CTN parameter update procedure) that it has assumed to be the CTN active tier 1 server and boosts the CTN based on its own time of day clock. The failed tier 1 server is defined as tier 0 and can re-enter the network after recovery, but not as tier 1 server, in the present embodiment. In addition, in an impersonation, if the primary server rejoins CTN as a layer 2 server, it assumes the role of the stratum-1 backup server. The console can instruct the primary server to resume its role as stratum-1 active server for CTN, if desired.

A personification of the associated logic detecting a failure in the active stratum 1 server and performing the recovery is described with reference to Fig.

15. Initially, the inactive layer 1 server detects a failure in the active layer 1 server, 1500 STEP. There are several mechanisms for detecting a failure in the active layer 1 server, including, for example, receiving a layer 1 system verification signal (SCS); via console assisted recovery, which includes communicating with the console to determine that the tier 1 active server has entered a stop check or powered off state; and through a triad recovery, which uses a third party server, the referee server, to vote off stratum 1 active server. These failure detection mechanisms are described in more detail below.

In response to detecting an active layer 1 failure, the inactive layer 1 server performs an acquisition process, 1502 STEP. In addition, it must detect stratum 1 active server entered a fault state, STEP 1504. it performs a delivery procedure to give up its role as stratum-1 active server for CTN, STEP 1506.

As an example, 1500 steps and 1502, which are performed by the inactive server layer 1, can be performed substantially in parallel with steps 1504 and 1506, which are performed by active layer 1.

For more details on the error detection and recovery of failures are described below with reference to the procedures that are based on

-42 / 64type of configuration. For example, stratum-1 server recovery is performed only when an alternate stratum-1 server has been specified in the CTN system-1 configuration. An alternative is specified in both the dual server and the triad configurations. Thus, a recovery procedure is a prerequisite for retrieving a dual server layer 1 configuration and a triad 1 layer configuration recovery, each of which is described below.

In a dual tier 1 configuration recovery, the inactive tier 1 server in the dual server configuration assumes the role of the tier 1 active server in response to detecting an active tier 1 failure. A personification of the logic associated with a dual tier 1 configuration recovery is described with reference to Fig. 16. Initially, the inactive tier 1 server detects a failure in the active tier 1, 1600 STEP server. A layer 1 active failure is detected in a dual server configuration when, for example, a console assisted recovery procedure is performed and indicates that a layer 1 active failure, or a layer 1 system check signal is recognized, each of them is described below.

In response to detecting the failure of the tier-1 active server, the inactive tier-1 server performs an active tier-1 acquisition procedure to assume the role of the tier-1 active server for CTN, 1602 STEP. This completes the transformation of layer 1 dual server configuration recovery.

In addition to layer 1 dual server configuration recovery, layer 1 triad configuration recovery is provided. A personification of the logic associated with retrieving layer 1 triad configuration is described with reference to Fig. 17. Initially, layer 1 server inactive in a triad configuration recognizes a failure of layer 1 active, 1700 STEP. As examples, the inactive layer 1 server recognizes an active layer 1 failure when a triad recovery process is performed and indicates that an active layer 1 failure has occurred; or a procedure

-43 / 64 assisted console recovery is performed when it indicates that a stratum 1 asset fails.

In response to detecting an active layer 1 layer, the inactive layer 1 server performs an active layer 1 acquisition procedure to assume the role of the CTN active layer 1 server, 1702 STEP. In addition, the active stratum 1 server takes up the role of the active stratum 1 server, in response to detecting that it lost the attachment for both the inactive stratum 1 server and the referee server, STEP 1704. The active layer 1 server performs a delivery layer 1 active process, described below, to abandon the role of the CTN layer 1 active server.

In addition, the inactive layer 1 server performs the triad recovery procedure, STEP 1706, when, for example, the following conditions occur: the inactive layer 1 server loses the attachment to the active layer 1 server and has an attachment for the referee; and / or the inactive tier 1 server recognizes a tier 1 active communication timeout and has an attachment for the referee. It is an active communication timeout of layer 1 detected, for example, two seconds until the expiration of a freewheel interval for CTN and allows the acquisition of layer 1 to occur before the sync check conditions being detected in CTN. Details on the freewheel range are described in the US Serial No. 11 / 468,352, “Coordinates Timing Network Configuration parameter Update internal,” Carlson et al., Presented on August 30, 2006, the right that remain is incorporated here by reference in its entirety.

In a personification, if the triad recovery fails, survey 1707, inactive stratum 1 server in a triad configuration performs a dual server recovery, as described with reference to Fig. 16, 1708 STEP. However, if successful, triad recovery, then dual server recovery will be ignored. This completes the transformation of layer 1 triad configuration recovery.

More details on various procedures performed during recovery are described in detail below.

-44 / 64For example, a mechanism for detecting a failure in the stratum-1 active server is the receipt of a stratum-1 system check signal (SCS) on the stratum-1 inactive server. This layer 1 system check signal indicates to layer 1 server in a dual server CTN configuration that layer 1 active server has entered a state that prevents it from continuing to act as layer 1 active server for CTN.

The inactive layer 1 server recognizes the SCS when it detects that the active layer 1 server has ended STP connectivity to the inactive layer 1 server. Inactive layer-1 detects that layer-1 the active server has ended

STP connectivity when it receives an offline signal in the last path of the STP path group associated with stratum 1 active server.

The tier 1 active server recognizes that it issued the SCS, when it ends all connectivity to the tier-1 inactive server. Active stratum 1 server considers all STP connectivity to the stratum 1 server inactive to have been terminated, when it sends an offline signal in the last path of the STP path group associated with the active stratum 1 server.

Another failure detection mechanism is the assisted console recovery procedure, which is initiated by the tier 1 inactive server on a dual server or triad configuration to determine the state of the tier-1 active server. This procedure makes use of information provided by the console to determine if an active layer 1 fault condition exists.

A personification of the logic associated with an assisted console recovery procedure is described with reference to Fig. 18A. Initially, inactive tier 1 server requests Server state, 1800

STEP. In particular, the inactive tier 1 server issues an STP request server generated State console commands with the node descriptor field in the equal block request command for the tier-1 active server node descriptor. In response to the console receiving this request, the console attempts to communicate with the active tier 1 server to determine the

Strat 1 active server state, 1802 STEP.

-45 / 64After trying to determine the status of the active stratum 1 server, the console issues a recording server state console commands to the inactive stratum 1 server with the state code in the request block set to the most well-known state of the strat 1 active server, 1804 STEP. If the inactive layer 1 server receives a recording server state console command indicating that the layer 1 server is in check stopped or disconnected from the state, which recognizes an active layer 1 condition, 1806 STEP.

More details associated with an example of assisted console recovery 10 are described with reference to the configuration shown in Fig. 18B. For example, in the dual server configuration, console assisted recovery is performed by the inactive server tier 1 when it detects a communication error from the attached server with the active tier-1 server. In the following example, the active server of layer 1 entered the Selection State. The following actions are performed during assisted console recovery for the configuration in fig. 18B.

1. Server D (1850) detects loss of attachment to server A (1852).

2. Server D issues the state request server command at the console to request the status of server A.

3. The console queries Server A to determine its health.

4. The console issues a recording server state to Server D indicating that server A is not operational (checkstopped or diesel off) or the operational state is unknown.

5. If server A is operational, or its state is unknown, Server D repeats the request server's state command.

-46 / 646. If Server A status is not operational, D

Server performs the CTN parameter update procedure to schedule a new layer-1 configuration to define itself as a layer-1 active server.

For example, the network timing coordinate parameter update procedure updates the CTN parameters simultaneously on the calendar network. The procedure includes, as an example, selecting one or more time parameters to change and building an information response package that includes the parameters to be changed, as well as when the change is taking place. The packet is then transmitted to the other servers on the network. On the receiving server, it is determined whether or not communication with the clock source has been lost. This is usually accomplished by periodically receiving a timing message from a network node that is used as a time clock source. If it is determined that the loss of communication has persisted too long (which is set ahead of time for the network and is a function of the maximum rate drifted from the clock on a server to the clock on that server's clock source, for example), then the receiving server declares its time parameters invalid. Then, the server acquires new Timing parameters. If it is not too long, the time parameter is still valid and the parameter is updated at the suggested future time on all servers on the network.

7. When layer 1 configuration change takes effect, the D Server issues a configuration change notification to the console.

8. Server C (1854) stratum-3 changes; changes (1856) Server F stratum-2.

9. A configuration change machine check is generated on all servers in the network to report layer 1 configuration change and layer level change for C and f servers.

-47 / 64A most common recovery procedure is the triad recovery procedure. The triad recovery procedure is performed by the inactive stratum 1 server in a triad configuration to determine whether a stratum-1 failure has occurred.

A personification of the logic associated with the triad recovery procedure is described with reference to Fig. 19A. Initially, the inactive tier 1 server is placed in the acquisition mode state, STEP 1900. In addition, a referee acquisition mode message command set is issued to the referee server, 1902 STEP. The set referee acquisition mode operation is issued, for example, through a message to the referee server by the alternate stratum server 1 to put the referee in the acquisition mode. The receiving server resumes a referee flag for the acquisition of the State and a response block. In the command message data field, the layer 1 active communication timeout flag is set as follows: the flag is set, for example, 0, if the server does not have an attachment for the active layer server; the flag is set to, for example, 1, if the server has an attachment for the active layer server and an active communication of layer 1 has been recognized.

If the response to the referee acquisition mode message command sets the acquisition status flag to 1, the inactive layer 1 server recognizes an active layer 1 failure; if the response to the set arbitrator acquisition mode message command has an acquisition status flag equal to 0, the inactive layer 1 server does not recognize an active layer 1 failure and performs the following; if the response has the active communication timeout flag of layer 1 equal to 1, the server goes out of acquisition mode; if the response has the active communication timeout flag of layer 1 equal to 0, the inactive layer-1 remains in acquisition mode.

The inactive layer 1 server leaves the acquisition mode, when any of the following occurs:

• she receives a public message response for the acquisition of a joint arbitrator containing the

-48 / 64acquisition of flag equal to 0 and the communication timeout flag equal to one.

• He issues a redefine command of the acquisition mode command to the referee. The replacement referee acquisition mode operation is issued to the referee server by the alternate stratum 1 server to take the referee out of the acquisition mode. This operation is forwarded to the referee server via a message.

• Performs an active layer 1 acquisition process.

If the inactive tier 1 server receives an established STP path message command from tier 1 active server in acquisition mode, it issues the acquisition mode command reset arbiter to the arbiter; and establishes the initiative to perform STP path initialization on paths to the active stratum-1 server.

When the referee server receives a set referee acquisition mode command from the inactive stratum 1 server, it enters referee acquisition mode. It leaves arbitrary acquisition mode when it occurs by any of the following:

• The referee responds to a public message command of referee acquisition together with the response that includes the acquisition state flag equal to 0 and a communication timeout flag equal to 1.

• The referee accepts an arbitrator acquisition mode command to reset stratum 1 inactive server.

• The referee receives a stratum-1 configuration update.

-49 / 64While the mode of acquisition of arbitrator, the arbitrator is in one of the following states acquisition arbitrators: acquisition pending State; or acquisition of active state. The referee acquisition status is indicated in response to the defined referee acquisition mode command.

The referee introduces the pending State acquisition when he enters the referee acquisition mode and both of the following conditions exist: The referee is attached to the active stratum-1 server; and a strat 1 communication active waiting time does not exist at the referee.

The acquisition pending status indicates that the stratum 1 10 inactive server cannot perform stratum-1 active acquisition. The referee leaves pending state acquisition when he enters the active state acquisition or when the referee leaves the referee acquisition mode.

The referee enters the active acquisition state in the following circumstances: there are · when he enters referee acquisition mode and any of the following conditions: active stratum 1 server not attached to the referee, or strat 1 active server accompanies the referee and a condition timeout of active communication of stratum 1 was recognized, the referee.

• When the acquisition is pending status and the active stratum 1 server leaves the attached state, or the active stratum-1 communication timeout is recognized.

The active acquisition state indicates to the inactive layer-1 server that it can perform an active layer-1 acquisition. There is one if the arbitrator enters the active acquisition state after responding to the joint acquisition command arbitrators, the arbitrator questions the active acquisition command (ie sends a message) from the referee to the inactive strat-1 server to indicate that he has transitioned from the acquisition pending for the active acquisition state.

-50 / 64When the referee enters the active acquisition state, any remaining paths from the path group to the active server of stratum 1 are placed in the uninitialized state indicating a communication error. While in the active acquisition state, the referee responds with the active state acquisition response code to the message commands to establish STP Path (ESP) of the active stratum-1 server.

The arbitrator leaves the acquisition pending State when the arbitrator leaves the acquisition mode.

An example of stratum 1 recovery in a 10-triad configuration is described with reference to Fig. 19B.

1. Server 1 (1950) goes on a state stop check.

2. Server 2 (1952) detects attachment loss for Server 1.

3. Server 2 issues a joint acquisition mode control command to the referee server.

4. The referee enters acquisition mode in response to the command to define acquisition mode as follows:

• if he has no attachment to server 1, he replies that 20 entered the active acquisition state indicating the inactive tier 1 server can assume the role of the tier-1 active server. When in the active acquisition state, the referee's server does not allow paths established with the active stratum-1 server.

· If he has no attachment to server 1, he replies that he has entered the pending acquisition State indicating that the inactive tier 1 server cannot assume the role of the tier-1 active server. If the referee loses his attachment to the

-51 / 64Server 1 while on acquisition pending State, it issues the referee active notification State acquisition to Server 2.

5. The referee indicates that he is in active acquisition status, the command set acquisition mode or with the command arbitrators Status acquisition notification active Server 2.

6. Server 2 performs the CTN parameter update process and has established it as the stratum-1 asset.

7. When the stratum-1 configuration change becomes current, Server 2 issues a configuration change notification change to the console.

8. A configuration change machine check is generated on all servers in the network to report the stratum-1 configuration change.

As a larger example, with reference to Fig. 19C, a recovery procedure is described for the acquisition of layer 1 server after the loss of links to active S1.

1. With respect to Fig. 19C, it is shown that server 2 (1972) and the referee (1974) detect loss of attachment to Server 1 (1976).

2. Server 2 issues the set acquisition mode control command to the referee server.

3. The referee indicates himself in the active acquisition status, either in response to the command setting the acquisition mode or with the acquisition status of the active referee, the notification command for server 2, indicating authorizes an acquisition.

4. Server 2 performs the CTN parameter update process and has established it as the stratum-1 asset.

-52 / 645. When the layer-1 configuration change becomes current, Server 2 issues a configuration change notification to the console.

6. Server 1 detects loss of attachment for servers 2 and 3 and performs the delivery procedure. Sends stratum-3 as a result of its attachment to Server B.

7. A request to interrupt the computer's configuration change check is generated on all servers in the network to report, the configuration change of layer 1 and that 1 Server is in layer-3.

In the following example, a layer 1 acquisition is not performed. This is described with reference to Fig. 19D. In this example:

1. Server 2 (1980) detects attachment loss for Server 1 (1982).

2. Server 2 issues the set acquisition mode control command to the referee server (1984).

3. The referee indicates that the response to the set command of acquisition mode is in the pending acquisition State, indicating that the inactive tier 1 server cannot assume the role of the tier-1 active server.

4. Server 2 does not perform recovery and falls to stratum-3.

5. If the link is restored, Server 2 issues the replacement acquisition mode command to the referee.

6. Server 2 generates a configuration change machine selection request to report a change in stratum level.

-53 / 64 Both the recovery of double layer 1 (Fig. 16) and the recovery of layer 1 triad (Fig. 17) an active layer 1 acquisition process is performed by inactive layer 1 server in response to recognize the failure of stratum 1 active. The process results in the inactive layer 1 server taking on the role of the active layer-1 server for CTN.

A personification of the logic associated with an active layer 1 acquisition is described with reference to Fig. 20. Initially, all remaining paths from the path group to the layer 1 active server are placed in an uninitialized state with the URC indicating a communication error, STEP 2000.

In addition, the server sets its tier 1 level, STEP 2002, and the block of configuration information for tier-1, the server and console is modified, STEP 2004. An example, the SCIB is modified such that the active bit is modified to indicate the server as stratum-1 active server; stratum 1 maximum short skew rate change field is set to the value for the server; the stratum-1 configuration timestamp is set to the current time; and the other fields are not modified.

In addition to the above, the server performs the CTN parameter update procedure to modify the stratum-1 configuration information block for CTN to the value in the updated SCIB, STEP 2006. The stratum 1 update time and the new stratum-1 configuration information block is defined as the 1 hour stratum configuration stamp in SCIB. This concludes active stratum-1 acquisition.

A still more performed procedure is the stratum-1 active procedure of delivery, which is performed in a double triad or server configuration by the stratum 1 active server, when it recognizes that the active state of stratum-1 active server has entered. . The results of the procedure in stratum 1 active server give up the role of stratum-1 active server for the CTN.

A personification of the logic associated with the tier 1 active delivery procedure is described with reference to Fig. 21. An example, the

-54 / 64paths and groups path for stratum 1 servers and inactive arbitrators at stratum 1 active server are defined as the Uninitialized state with the URC indicating non-complete startup, STEP 2100. In addition, the active tier 1 server defines its layer 0 and becomes a secondary server, STEP 2102. Former layer 1 server active as a secondary server defines its layer 1 configuration to the null configuration, STEP 2104. In addition, it tries to locate a potential clock source, through its connections, STEP 2106. This completes the delivery process.

As described above, the Request 10 Server State command is used to request the operational status of the server specified by the node descriptor in the request block. The status of the specified server is provided asynchronously by the console using the written Server Status command. One embodies a command request block for the command

Request server status is described with reference to Fig. 22A.

Block request for server state request 2200 included, for example, the following:

a) 2202 length: this field includes a value specifying a command block length.

b) the code 2204 command: this field specifies the Read server status command.

c) number of transactions for the 2206 command: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

d) node descriptor 2208: this field includes a server node descriptor for which status is being requested.

A personification of a 2250 command response block from the request server State command is described with reference to Fig.

22B. Response block 2250 includes, for example:

-55 / 64a) 2252 in length: this field includes a value specifying a command block length.

b) response code 2254: this field includes the response code of the command.

c) number of transactions of the 2256 command: this field includes the value provided in the command numeric transaction field of the command request block.

The recording server Status command provides the operational status of the server specified in the order block. The command is issued by the console after accepting a State command from the request server. A personification of a command request block for the recording server Status command is described with reference to Fig. 23A. An example, a recording server state request block 2300 includes the following:

a) 2302 in length: this field includes a value specifying a command block length.

b) the code 2304 command: this field includes a value specifying the recording server's Status command.

c) number of transactions of the command 2306: this field includes a value that is associated with the command being issued. The command transaction number is returned in the command response block.

d) State code 2308: this field includes a value indicating the Server State specified by the node descriptor in the request block. States include, for example: · The server is operational.

• The state of the server is unknown.

• The server is in the checkstopped state.

-56 / 64 • The server is turned off.

e) the node descriptor 2310: this field includes the node descriptor of the server being informed status.

One embodies the command response block for the recording server status command 5 is described with reference to Fig. 23B. For example, a recording server state response block 2350 includes the following:

a) 2352 in length: this field includes the value specifying a command block length.

b) response code 2354: this field includes the response code of the command.

c) number of transactions of the 2356 command: this field includes the value provided in the command numeric transaction field of the command request block.

In a personification, one or more aspects of the present invention can be performed in a processing environment based on one architecture, which can be referred to as a native architecture, but which emulates the architecture of another, which can be referred to as a guest architecture . As examples, the native architecture is the Power4 or PowerPC ® architecture offered by the International Business Machines Corporation, of Armonk, Nova

York or an Intel ® architecture, offered by Intel Corporation; and z / architecture ® guest architecture also offered by International Business Machines Corporation, Armonk, New York. Aspects of architecture / z® are described in the “z / architecture, principles of operation,” IBM publication does not. SA22-7832-04, September 2005, are hereby incorporated by reference in their entirety. In such an instruction and / or logic environment, which is specified in the z / architecture ® and designed to run on a z / architecture ® machine, it is emulated to run on a different architecture to z / architecture ®. An example of this processing environment is described with reference to FIGs. 24-25.

-57 / 64 Referring to Fig. 24, an embodiment of a processing environment is described for incorporating and using one or more aspects of the present invention. The 2400 processing environment includes, for example, a central native Processing unit 2402, a 2404 memory (for example, the main memory) and one or more input / output (I / O) 2406 devices linked together through, for example, example, one or more 2408 buses and / or other connections. As an example, a 2400 processing environment may include a Power PC ® processor, a pSeries ® server or an xSeries ® server offered by International Business Machines Corporation, Armonk, New York; an HP Superdome with Intel ® Itanium ® 2 processors offered by Hewlett-Packard Company, Paio Alto, California; and / or other machines based on architectures offered by IBM ®, Hewlett-Packard, Intel ®, Sun Microsystems or others. Poder PC ®, pSeries ® and xSeries ® are registered trademarks of International Business Machines Corporation, Armonk, New York, USA. Intel ® and Itanium ® 2 are registered trademarks of Intel Corporation, Santa Clara, California.

Native central processing unit 2402 includes one or more native records 2410, as one or more general purpose records and / or one or more special purpose files, used during processing within the environment. These records include information that represents the state of the environment at any specific time in time.

In addition, native central processing unit 2402 executes instructions and code that are stored in memory 2404. A specific example, central processing unit executes emulator code 2412 stored in memory 2404. This code allows the processing environment configured in an architecture to emulate another's architecture. For example, the 2412 emulator code allows machines based on architectures other than az / architecture, such as Power PC ® processors, pSeries ® servers, xSeries ® servers, HP Superdome ® servers or others to emulate az / architecture ® and run the software and instructions developed based on z / architecture ®.

-58 / 64More details regarding the 2412 emulator code are described with reference to Fig. 25. Guest instructions 2502 include software instructions (for example, machine instructions) that were developed to run on an architecture other than the native 1002 CPU. For example, 2502 guest instructions may have been designed to run on the 902 z® processor architecture, but are instead being emulated on the native CPU 2402 (which may be, for example, an Intel® Itanium® 2 processor). An example, emulator code 2412 includes an instruction seeking 2500 routine to obtain one or more 2502 guest instructions from memory 2404 and optionally provide local buffer for the obtained instruction.

Further emulator code 2412 includes a 2504 routine translation instruction to determine the type of guest instruction that has been obtained and provide one or more native 2509 instructions that correspond to the guest instruction. For example, provisioning includes creation during, for example, processing a translation, a native flow of instructions for a particular guest's instruction. This includes identifying the function and creating the equivalent native instructions. In yet another example, providing native instructions includes selecting a code segment in the emulator associated with the guest instruction. For example, each guest instruction with an associated code segment in the emulator, which includes a sequence of one or more native instructions, and that code segment is selected to be executed.

Further emulator code 2412 includes a 2506 emulation control routine causing the native instructions to be executed. Emulation control 2506 routine can cause native CPU 2402 to execute a native instruction routine that emulates one or more previously obtained guest instructions and, upon completion of such execution, to return control to the instruction fetch routine to emulate the obtaining the next guest instruction or guest instruction group. Execution of native instructions 2509 may include loading data into a 2404 memory register; storage of data for memory in a register; or perform some kind of arithmetic or logical operation, as determined by the translation routine.

-59 / 64Every routine is, for example, implemented in the software, which is stored in memory and executed by the native central processing unit 2402. Other examples, one or more operations or routines are implemented in the firmware, hardware, software or some combination of these . The records of the guest emulated processor can be emulated using the 2410 registers of the native CPU or using locations in memory 2404. In the embodiments, the guest instructions 2502, native instructions 2509 and code emulation 2412 may reside in the guest's memory or may be dispersed among different memory devices.

In yet another embodiment, data processing is a system suitable for storing and / or executing usable program code that includes at least one processor linked directly or indirectly to memory elements via a system bus. Memory elements include, for example, local memory used during the actual execution of program code, mass storage and cache memory, which provide temporary storage of at least some program code to reduce the number of times that code must be recovered from mass storage during execution.

Input / Output or I / O devices (including, but not limited to, keyboards, monitors, pointing devices, DASD, tape, CDs, DVDs, thumb drives and other memory media, etc.), can be coupled to the system directly or through the intermediate L / O controllers. Network adapters can also be linked to the system to enable the data processing system to become linked to other data processing systems or remote printers or storage devices over private or public intermediary networks. Modems, cable modems and Ethernet cards are just a few of the available types of network adapters.

One or more aspects of the present invention can be included in an article of manufacture (for example, one or more computer program products), having, for example, the computer's usable media. The media has it, for

-60 / 64instance, computer readable program code or logic means (e.g., instructions, code, commands, etc.) to provide and facilitate the capabilities of the present invention. The article of manufacture can be included as part of a system (for example, the computer system) or sold separately.

An example of an article of manufacture or a computer program product incorporating one or more aspects of the present invention is described with reference to Fig. 26. A computer program product 2600 includes, for example, one or more computer usable media 2602 for computer storage program readable code means or logic 2604 to provide and facilitate one or more aspects of the present invention. The medium can be an electronic magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a means of propagation. A semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read - only memory (ROM), a hard magnetic disk and an optical disk are examples of readable media from computer. Examples of optical discs read-only compact disc (CD-ROM), compact disc read / write (CDR / W) and DVD.

A sequence of program instructions or a logic assembly of one or more interrelated modules defined by one or more computer readable program codes means or logic to direct the performance of one or more aspects of the present invention.

Described here are features that facilitate the maintenance of time synchronization by multiple different computer systems to form a coordinated timing network. Timing network servers take advantage of the server time protocol to pass timekeeping information over existing high-speed data links between systems that provide the ability for the time of day clocks on each system to be synchronized with the accuracy required at the high end today's computer systems. The use of STP over high-speed, low-latency links

-61 / 64 offers the ability to synchronize all systems in the CTN to accuracy, for example, a few microseconds based on a reference period provided by a single server.

STP provides the ability to define and maintain timekeeping information within the CTN, such as time zone, summer savings time offset and a jump seconds offset. The information can be updated within the scope of CTN in a programmed and coherent manner, changes occurring all at the same time on all CTN servers. This avoids the potential system risks and disruptions that occur when these parameters are updated occasionally, creating discrepancies in time settings between computers.

CTN parameters can be defined and read by an operator via the STP console interface. CTN parameters include server connectivity, local time information, such as time zone and summer time savings and the jump seconds needed to calculate UTC. The console itself is any element that provides an operator interface to display and define the CTN parameters, and that has the ability to communicate with the STP facility.

In one aspect of the present invention, a single tier-1 active server is provided as the clock source for the network. The time of day clock on stratum 1 active server can be set to any time, but in general, it is defined as an external time reference, such as a dial up to UTC. Other servers are allowed to join the CTN, if they have an undefined layer 1 configuration, known as a null configuration, or if they have a layer 1 configuration that corresponds to the primary time server. Thus, the synchronization accuracy within the CTN is not dependent on the quality of an external time source or even the existence of an external time source on the stratum-1 server. This ensures the synchronization of servers in the CTN until the same main reference root.

In another aspect of the present invention, an alternative server is defined such that it is able to take over as an active layer server in case of

-62 / 64a failure in the active stratum-1 server. This prevents a single point of failure for the CTN, such that servers in the CTN can maintain or recover synchronization within the timing network despite a failure in the stratum active server1.

Additional information regarding timing networks is provided in the following patent applications: USA no. series 60 / 887,512 called “Time Server Protocol Messages and Methods”; USA. serial no. 60 / 887,544 called “Channel Subsystem Server Time Protocol Commands”; USA serial number 60 / 887,584 called “Facilitating the Synchronization of Servers in a Coordinated Timing Network”; USA serial number 60 / 887,586 called “Facilitating Recovery in a Coordinated Timing Network”; USA Serial No. 11 / 468,352, called “Coordinated Network Timing Configuration Parameter Update Procedure” August 30, 2006 filed: USA ,. at the. series 11 / 460,025, called '' Information that can be obtained directly through Application Programs usable in determining the accuracy of the watch, ”filed July 26, 2006; USA Serial No. 11 / 223,886, called “System and Method for the beacon of TOD-clock” USA. Serial No. 11 / 532.168, called “Synchronism Signal for the adjustment of the beacon adjustment of the TOD-clock; ”USA serial number 11 / 468.501, called“ Controlling Data Access through a loop only, if the locking facility is changed ”USA serial number 11 / 223.878, called“ Clock Filter Dispersion ”USA Serial No. 11 / 223,876, called “Method and System for estimating clock displacement and deviation; ”USA. serial number 11 / 223,577, called “Use of T4 Timestamps to calculate the deviation and displacement of the clock and the USA. Serial No. 11 / 223,642 called “System and Method to calibrate TOD's clock.”

Advantageously, one or more aspects of the present invention allow for the provision of quality timekeeping information allowing synchronization and precision requirements to be met. Systems within CTN continue to be tightly synchronized with a less stringent requirement for synchronization accuracy for an external time source, such as UTC.

-63 / 64Use of expensive dedicated Timing links and / or a separate external box is not necessary. In addition, the requirement for each server to attach to an external time server or to have GPS is not necessary.

Although one or more examples have been provided here, they are only examples. Many variations are possible without abandoning the spirit of invention present. For example, processing environments other than the examples provided herein may include and / or benefit from one or more aspects of the present invention. In addition, the required environment may not be based on z / architecture ®, but may instead be based on other architectures offered by, for example, IBM ®, Intel ®, Sun Microsystems, as well as others. Even further, the environment can include multiple processors, and / be partitioned or linked to other systems, as examples.

In addition, although several control blocks have been described, each of these control blocks may include additional, less and / or different information. The location within the control block and the size of each field within the control block can vary for different embodiments.

As used herein, the expression “obtain” includes, but is not limited to, seeking, receiving, having, providing, being provided, creating, developing, etc.

The features of one or more aspects of the present invention can be implemented in software, firmware, hardware or some combination thereof. Program at least one machine-readable storage device comprises at least one program of instructions executable by the machine to perform the capabilities of the present invention can be provided.

The flow diagrams mentioned here are just examples. There can be many variations on these diagrams or the steps (or operations) described without abandoning the spirit of invention. For example, steps can be performed in a different order, or steps can be added, deleted or modified. All of these variations are considered a part of the claimed invention.

-64 / 64Although embodiments have been described and described in detail here, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions and the like can be made without departing from the spirit of invention, and these are therefore considered in the scope of the invention defined in the claims.

-I / 4-