Cluster Routing and Management Diversity (CRMD)

The Cluster Routing and Management Diversity feature eliminates the need for a full point code entry in the routing table to route to every signaling point in every network. The Cluster Routing and Management Diversity feature allows the EAGLE to configure one routeset to a entire cluster of destinations. This feature also allows the EAGLE to manage and switch traffic to more end nodes.

A cluster is defined as a group of signaling points whose point codes have identical values for the network and cluster fields of the point codes. A cluster entry in the routing table is shown with an asterisk (*) in the member field of the point code, for example, 111-011-*. With this feature, ANSI destination point codes can be specified as either a full point code, for example, 123-043-045, or as a cluster of signaling point codes, for example, 111-011-*.

Note:

Cluster entries can only be provisioned as ANSI destination point codes. Cluster entries cannot be provisioned for ITU international or ITU national destination point codes. The ANSI alias point code for an ITU international or ITU national destination point code must be a full point code.

The Cluster Routing and Management Diversity feature allows provisioning of clusters, as well as of full point codes that belong to the same cluster as destination point codes (Figure 2-21). The point codes 111-011-*, 111-011-005 and 111-011-045 entries can be provisioned. In Figure 2-21, the cluster destination point code 111-011-* represents all the point codes of the cluster except for point codes 111-011-005 and 111-011-045. Cluster entries in the destination point code table can also be used as a DPC for a route. A group of such routes with varying relative cost forms a routeset to a cluster, just like a routeset to a full point code.

Figure 2-21 Cluster Routing and Management Diversity

Exception Lists (X-lists)

An exception list for a cluster is a list of point codes in a cluster whose routes are more restricted than other routes to that cluster. The term “more restricted” is used when comparing the route status of a cluster member to the route status of the cluster. A PROHIBITED status is more restrictive than a RESTRICTED status, and a RESTRICTED status is more restrictive than an ALLOWED status.

This list contains point codes that are not assigned to any individual routeset, and the only routeset to that node is through a cluster routeset. The exception list is a dynamic list that changes when the status of the cluster routesets changes.

The EAGLE allows users to specify whether exception list entries need to be created on a per cluster basis. For each cluster, the user can specify an exception list exclusion indicator (ELEI) when configuring the cluster point code with the ent-dstn command. When the ELEI is yes, the EAGLE does not create exception list entries or remove any existing exception list entries for the given cluster. When the ELEI is no, the EAGLE creates and removes exception list entries. When the ELEI is no, it is not guaranteed that there will be space available to create each and every possible exception list entry for provisioned cluster entries. All such exception list entries must compete for available exception list space.

Exception list entries are stored as an extension of the Destination Point Code table. The Destination Point Code table can contain a maximum number of entries, as shown in Table 2-5. The EAGLE allows the user to specify the number of entries reserved for the exception list. Table 2-5 also shows the number of entries that can be reserved for the exception list and the number of entries that are reserved for configured destinations (the full, cluster point codes, and network routing point codes).

Table 2-5 Maximum Point Code Quantities

Feature Status	Maximum DPC Quantity	Number of Entries Reserved for the Exception List	Maximum Number of Full, Cluster, and Network Routing Point Codes
The 5000 Routes feature is off and 6000, 7000, 8000, or 10,000 routesets are not enabled	2500	500 - 2000	2500 minus the number of entries reserved for the exception list.
The 5000 Routes feature is on and 6000, 7000, 8000, or 10,000 routesets are not enabled	5500	500 - 5000	5500 minus the number of entries reserved for the exception list.
6000 routesets are enabled	6500	500 - 6000	6500 minus the number of entries reserved for the exception list.
7000 routesets are enabled	7500	500 - 6000	7500 minus the number of entries reserved for the exception list.
8000 routesets are enabled	8500	500 - 6000	8500 minus the number of entries reserved for the exception list.
10,000 routesets are enabled	10500	500 - 10000	10500 minus the number of entries reserved for the exception list.

The outputs of the ent-dstn, dlt-dstn, chg-dstn, and rtrv-dstn commands display this destination point code usage information.

The number of configured full point codes
The number of configured cluster point codes
The number of configured network routing point codes
The sum of configured destinations (full, network routing, and cluster point codes)
The number of DPCs the EAGLE may contain (full, network routing, and cluster point codes). This number is the value of the chg-stpopts command’s mtpdpcq parameter. The mtpdpcq parameter value is not always the maximum number of entries minus the number reserved for the exception list. This calculation determines the maximum number of DPCs the EAGLE may contain. The mtpdpcq parameter value of the chg-stpopts command determines the actual number of DPCs the EAGLE can have, and can be set to an amount less than the maximum.
The number of entries reserved for exception list. This number is the value of the chg-stpopts command’s mtpxlq parameter.

The maximum number of alias point codes that can be in the EAGLE. The EAGLE can contain the quantities of alias point codes shown in Table 2-6 depending the features that are enabled or turned on.

Table 2-6 Maximum Alias Point Code Quantities

Feature Status	Maximum Alias Point Code Quantity
The 5000 Routes feature is off and 6000, 7000, 8000, or 10,000 routesets are not enabled	12000
The 5000 Routes feature is on and 6000, 7000, 8000, or 10,000 routesets are not enabled	12000
6000 routesets are enabled	12000
7000 routesets are enabled	8000
8000 routesets are enabled	8000
10,000 routesets are enabled	10000

The number of alias point codes configured in the EAGLE.

Exception list entries have an expiration timer. There is a single EAGLE-wide expiration timer value for exception list entries. The exception list expiration timer, the size of the exception list, and the percentage of occupancy that generates a minor alarm can be configured with the chg-stpopts command. The values are shown in these fields of the rtrv-stpopts command output:

MTPXLQ = the maximum number of entries the exception list (x-list) can contain.

MTPXLET = the maximum amount of time the EAGLE will maintain an unreferenced exception list (x-list) entry

MTPXLOT = the exception list (x-list) occupancy threshold (in terms of percentage of space available). If this threshold is exceeded, the EAGLE raises a minor alarm. The percentage of occupancy refers to the number of exception list entries as compared to the maximum number of entries the exception list can hold. For example, if there are 1500 entries configured for the exception list and the exception list contains 1000 entries, the percentage of the exception list space being used is 66%. If this threshold is exceeded, the EAGLE raises a minor alarm.

The EAGLE raises a major alarm when the exception list becomes completely full and the EAGLE fails to create any more exception list entries.

MTPDPCQ = the maximum number of destination point codes that can be configured in the EAGLE.

The sum of the MTPDPCQ and MTPXLQ values (the maximum DPC quantity) cannot exceed the totals shown in Table 2-5 depending on the features that are enabled or turned on.

An exception list entry’s timer is restarted when an exception list entry gets created, updated, or used for routing. This expiration timer (the mtpxlet parameter in the chg-stpopts command) can be set from a minimum of 20 minutes to a maximum of 24 hours. The default value for the expiration timer upon EAGLE start-up is 60 minutes. If the timer expires before it is restarted, the exception list entry is removed. The expiration timer allows the EAGLE to save resources, if the exception list entry is sitting idle for a long time.

An exception list entry can be created for three distinct set of conditions.

The first set of conditions creates exception list entries based on the status of the route (allowed, restricted, or prohibited), and these entries are marked as “exception list due to routing.”
The EAGLE creates an exception list entry to maintain the congestion status of a non-provisioned, cluster-routed destination point code. These entries are marked “exception list due to congestion.”
The EAGLE also creates an exception list to prohibit routing to a member of a cluster when circular routing to that member is detected. These exception list entries are marked “exception list due to circular routing.”

An exception list entry for a particular cluster can be removed from the exception list when these conditions are met.

The status of all routes to the specified point code changes to a status that is less or equally restrictive than the corresponding status of the cluster’s routes. This can happen for two reasons.
- A dact-rstst command was issued.
- A network management message (TFA or TFR) was received indicating the new status of the route to the specified point code.
The expiration timer for the exception list entry expires.
When a chg-dstn command is issued and changes the ELEI to yes for the cluster, and the EAGLE removes all exception list entries created for that cluster.
The chg-stpopts command was issued with the mtpxlet parameter, and the new value for the mtpxlet parameter was smaller than the original value. This command can change the allocation of routing table entries for the exception list. If the size of the exception list is reduced and the number of entries in the exception list is now greater than the new value of the mtpxlet parameter, the EAGLE will remove excess exception list entries at random.
When the user allows a circular routed “exception list due to circular routing” entry.
When congestion abates for an “exception list due to routing” entry.

Cluster Routing

When the EAGLE receives an MSU to route, the routing function looks for the MSU’s destination point code as a full point code entry in the routing table. If found, the full point code entry is used to find the corresponding routeset and the outgoing route. If a full point code entry is not found, the routing function uses the destination point code’s network and cluster values to find a cluster entry to which the destination point code belongs. If found, the cluster entry is used to find the corresponding routeset and the outgoing route. If neither a full point code entry or cluster point code entry is found, the EAGLE generates UAM 1004, “MTP rcvd unknown DPC.”

Compatibility with Non-Cluster Routing Nodes

It is possible that not all of the nodes in the network that the EAGLE is operating in are cluster routing nodes. In such a situation, those nodes not doing cluster routing will interpret TCx messages, and apply them to each individual point code belonging to the concerned cluster. This may cause an inconsistency in the status records for exception-listed point codes in different nodes. In order to avoid this situation, the EAGLE takes these steps:

After broadcasting a TCR message for a cluster, the EAGLE stops any level 3 T8 timers running for exception-listed members of the cluster, and enables TFPs for the cluster’s exception-listed (prohibited) member point codes by stopping the level 3 T8 timer. This allows TFPs to be sent for prohibited members immediately after a TCR is broadcast.
After broadcasting a TCA message for a cluster, the EAGLE enables a one-time TFR for the cluster’s exception-listed (restricted) member point codes by stopping the level 3 T18 timer, and enables the TFPs for the cluster’s exception-listed (prohibited) member point codes by stopping the level 3 T8 timer. This allows TFPs to be sent for prohibited members, and TFRs for restricted members, immediately after a TCA is broadcast.

Cluster Management and the ITU Network

ITU SS7 networks do not use the concepts of clusters of point codes and cluster network management messages. The EAGLE does not generate TCx messages toward ITU nodes. When the EAGLE is acting as gateway between an ITU network and an ANSI network, during the broadcast phase of TCx messages, the EAGLE does not send TCx messages to adjacent ITU point codes. It is possible that messages may be lost in such a case. In order to reduce message loss and quickly notify the sending ITU node about the status, the EAGLE enables TFPs or TFRs immediately (with the level 3 T8 or T18 timers stopped) and relies on the TFPs or TFRs to convey the status information.

While sending response method network management messages in response to a received MSU, the EAGLE checks the MSU’s originating point code. If the MSU’s originating point code is an ITU point code, a TFx message is returned.

Cluster Management When the Cluster Routing Feature is Turned Off

The Cluster Routing and Management Diversity feature is an optional feature that is turned off by default. To use the Cluster Routing and Management Diversity feature, it must be turned on by entering the appropriate command. Once this feature is turned on, it cannot be turned off. If this feature is turned off, the EAGLE does not send any cluster management messages or allow cluster destination point codes to be added to the destination point code table. The EAGLE is capable of processing incoming cluster management messages, even though the feature is turned off. When a cluster management message is received, the EAGLE treats this message as though network management messages were received for each full point code, configured in the destination point code table, that belongs to that cluster.

Cluster Routing and Management Diversity Rules

These rules apply to the Cluster Routing and Management Diversity feature.

If the provisioned number of exception list entries are already created, the EAGLE will not create any more exception list entries. The EAGLE raises an alarm in advance of such an occurrence, and pegs each occurrence of failure-to-create an exception list entry.
All adjacent point codes for linksets must be full point codes.
All entries in the remote point code table must be a full point code.
The EAGLE maintains the congestion status of only 100 destinations, including full point codes and point codes to which cluster routing is performed.
When the cluster routing feature is turned on, and the EAGLE receives an MSU and does not find a route with a full point code, a cluster route, or any other full point code route belonging to the cluster, the EAGLE will generate a TCP response.
When the cluster routing feature is turned off, and the EAGLE receives an MSU and does not find a route with a full point code, the EAGLE will generate a TFP response.

When the EAGLE is used as an ITU-ANSI gateway STP.

The EAGLE does not broadcast TCx messages toward the ITU nodes. Messages could be lost until the response method is initiated. It is recommended that the cluster routing feature not be turned on when the EAGLE is an ITU gateway STP.
Cluster destination point codes cannot have ITU alias point codes.

All ANSI alias point codes specified for real ITU point codes are required to be full point codes.

The point code specified in the ent-map command must use a full point code, and that full point code must be in the routing table.

The point code specified in the ent-gtt and ent-cspc commands can use either a full point code or a cluster point code, but these point codes must be in the routing table.

The EAGLE allows cluster routing for subsequent global title (GTT) messages. The EAGLE also sends subsystem status messages to concerned point codes using a cluster route. The EAGLE does not generate MTP status messages for point codes that the EAGLE is routing clusters to, so all point codes in the mated application table must be full point codes.

Gateway screening verifies the concerned point code in TFx/RSx messages received by the EAGLE. Gateway screening passes a TFx/RSx message through the MTP-affected destination test, if the concerned point code has either a full point code route or a cluster route.

Gateway screening verifies the concerned point code in TCx/RCx messages received by the EAGLE. Gateway screening passes a TCx/RCx message through the MTP-affected destination test, if the concerned point code has either a cluster route for a concerned cluster or a member route for any of the members of the concerned cluster.

If a point code is in the routing table as an exception-listed point code and the user enters a command (ent-dstn) to configure that same point code as a full point code, the exception-listed point code attribute is changed to a full point code attribute, and the exception-list related information from the cluster entry is updated.

When a cluster destination point code is removed from the EAGLE’s database, all related exception-listed point codes of that cluster are removed.

The EAGLE implements these protocol features that are non-preferred options.

The EAGLE broadcasts a TFP, when a full point code is prohibited and these conditions apply.
- The corresponding cluster is not provisioned.
- All other full point codes belonging to the same cluster are prohibited on the same route.
The EAGLE responds with a TFP, when a message is received for an inaccessible point code and the corresponding cluster does not exist.
Upon receiving a TCR message for a cluster that is not configured, the EAGLE marks all individually configured members of that cluster as restricted, and starts the RSR procedure for them.
Upon receiving a TCP message for a cluster that is not provisioned, the EAGLE marks all individually configured members of that cluster as prohibited, and starts the RSP procedure for them.
The EAGLE stops the level 3 T8 and T18 timers, after broadcasting a TCA for prohibited and restricted members of the clusters. These members can be exception-listed point codes or full point codes.
The EAGLE stops the level 3 T8 timers after broadcasting a TCR for prohibited members of the clusters. These members can be exception-listed point codes or full point codes.

The route assigned to a full point code DPC cannot be removed from the database if that DPC is a member of a cluster point code in the database.

If a route assigned to a cluster point code is removed from the database, all routes to any members of that cluster are also removed from the database.

Cluster Routing and Management Diversity Example

This section shows an example of the Cluster Routing and Management Diversity feature, and lists the network events affecting the EAGLE. This example is based on Figure 2-22 and Table 2-7.

Figure 2-22 Cluster Management

Table 2-7 Example Cluster Routing Information

	Route Table for Destination 005-005-001	Route Table for Cluster 005-005-*
1	LSN 1, Cost=10	LSN 1, Cost=10
2	LSN 2, Cost=15	LSN 2, Cost=15
3	LSN 3, Cost=20	LSN 3, Cost=20

When the normal routes, linksets LSN 1 and LSN 2, become available, the EAGLE sends a preventive TFP for destination 005-005-001 and a preventive TCP for cluster 005-005-* to node 002-002-002, and starts routing messages to destination 005-005-001 and cluster 005-005-* using linkset LSN 1. The EAGLE broadcasts TFAs about destination 005-005-001 and TCAs about cluster 005-005-* to all other adjacent nodes.

When linkset LSN 4 fails, node 002-002-002 sends a TFP for destination 005-005-001 to the EAGLE. Linkset LSN 4 is prohibited from carrying traffic from the EAGLE to destination 005-005-001. The EAGLE stops using linkset LSN 1 to send traffic to destination 005-005-001, performs forced rerouting, starts level 3 timer T11 for destination 005-005-001, and starts using linkset LSN 2 to send messages to destination 005-005-001. The EAGLE generates preventive TFPs about destination 005-005-001 to node 002-002-003. The preventive TCP for cluster 005-005-* sent to node 002-002-002 remains in effect.
When the level 3 timer T11 for destination 005-005-001 expires, TFRs are broadcast for destination 005-005-001 to nodes 004-004-004, 006-006-006, 007-007-007, and 008-008-008. Destination 005-005-001 is restricted.
When linkset LSN 5 fails, node 002-002-002 sends a TCP for cluster 005-005-* to the EAGLE. Linkset LSN 5 is prohibited from carrying traffic from the EAGLE to cluster 005-005-*. The EAGLE stops using linkset LSN 1 to send traffic to cluster 005-005-*, performs forced rerouting, starts the level 3 timer T11 for cluster 005-005-*, and starts using linkset LSN 2 to send messages to cluster 005-005-*. The EAGLE sends preventive TCPs for cluster 005-005-* on linkset LSN 2. The EAGLE sends a TCR for cluster 005-005-* on linkset LSN 1, to allow cluster 005-005-* and destination 005-005-001 to send messages back to the EAGLE on linkset LSN 1. When the level 3 timer T11 for cluster 005-005-* expires, the EAGLE sends a TCR for cluster 005-005-* to nodes 004-004-004, 006-006-006, 007-007-007, and 008-008-008. Cluster 005-005-* is restricted.
When linkset LSN 6 fails, node 003-003-003 sends a TCP for cluster 005-005-* to the EAGLE. The EAGLE performs forced rerouting, sends a preventive TFP for destination 005-005-001 and a TCP for destination 005-005-001 to node 004-004-004, and starts using linkset LSN 3 for sending messages to destination 005-005-001 and cluster 005-005-*.
When linkset LSN 7 fails, node 004-004-004 sends a TCP for cluster 005-005-* to EAGLE. The EAGLE cannot send traffic to either destination 005-005-001 or cluster 005-005-*. The EAGLE broadcasts TCPs for cluster 005-005-* to nodes 002-002-002, 003-003-003, 004-004-004, 006-006-006, 007-007-007, and 008-008-008. Cluster 005-005-* and destination 005-005-001 are inaccessible.
When linkset LSN 7 recovers, node 004-004-004 sends a TCA for cluster 005-005-* to the EAGLE. The EAGLE sends a preventive TCP for cluster 005-005-* to node 004-004-004, and starts using linkset LSN 3 to send traffic to cluster 005-005-*. The EAGLE sends a TCR for cluster 005-005-* to node 002-002-002. This allows cluster 005-005-* to send messages back to the EAGLE on linkset LSN 3. The EAGLE sends a preventive TCP for cluster 005-005-* to nodes 003-003-003 and 004-004-004. The EAGLE sends a TCR for cluster 005-005-* to nodes 006-006-006, 007-007-007, and 008-008-008. The EAGLE enables response method for destination 005-005-001, and starts a routeset test for destination 005-005-001 on linkset LSN 3. Cluster 005-005-* is restricted.
When linkset LSN 6 recovers, node 003-003-003 sends a TCA for cluster 005-005-* to the EAGLE. The EAGLE performs controlled rerouting on cluster 005-005-*, sends a preventive TCP for cluster 005-005-* to node 003-003-003, and starts using linkset LSN 2 to send traffic to cluster 005-005-*. The EAGLE sends a TCR for cluster 005-005-* to node 004-004-004. The EAGLE starts a routeset test for destination 005-005-001 on linkset LSN 2.
When linkset LSN 5 recovers, node 002-002-002 sends a TCA for cluster 005-005-* to the EAGLE. The EAGLE performs controlled rerouting, and starts using linkset LSN 1 to send traffic to cluster 005-005-*. The EAGLE sends a preventive TCP for cluster 005-005-* to node 002-002-002. The EAGLE broadcasts a TCA for cluster 005-005-* to nodes 003-003-003, 004-004-004, 006-006-006, 007-007-007, and 008-008-008. The EAGLE enables response method for destination 005-005-001, and starts a routeset test for destination 005-005-001 on linkset LSN 1. Cluster 005-005-* is allowed.
In response to the routeset test, node 004-004-004 sends a TFA for destination 005-005-001 to the EAGLE. The EAGLE performs controlled rerouting, and starts using linkset LSN 3 to send traffic to destination 005-005-001. The EAGLE sends a preventive TFP for destination 005-005-001 to nodes 003-003-003 and 004-004-004. The EAGLE sends a TFR for destination 005-005-001 to node 002-002-002 that allows destination 005-005-001 to send messages back to the EAGLE on linkset LSN 1. The EAGLE broadcasts a TFR for destination 005-005-001 to nodes 006-006-006, 007-007-007, and 008-008-008. Destination 005-005-001 is restricted.
In response to the routeset test, node 003-003-003 sends a TFA for destination 005-005-001 to the EAGLE. The EAGLE performs controlled rerouting and starts using linkset LSN 2 to send traffic to destination 005-005-001. The EAGLE sends a preventive TFP for destination 005-005-001 to node 003-003-003. The EAGLE sends a TFR for destination 005-005-001 to node 004-004-004.
In response to the routeset test, node 002-002-002 sends a TFA for destination 005-005-001 to the EAGLE. The EAGLE performs controlled rerouting, and starts using linkset LSN 1 to send traffic to destination 005-005-001. The EAGLE sends a preventive TFP for destination 005-005-001 to node 002-002-002. The EAGLE sends a TFA for destination 005-005-001 to nodes 003-003-003, 004-004-004, 006-006-006, 007-007-007, and 008-008-008. Destination 005-005-001 is allowed.

Home Cluster Example

Figure 2-23 Home Cluster Example

Table 2-8 Home Cluster Routing Information

	Route table for Destination 002-002-005	Route table for cluster 002-002-*
1	LSN 1, Cost=10	LSN 1, Cost=10
2	LSN 2, Cost=15	LSN 2, Cost=15

A home cluster is a cluster point code that contains either the true point code or any capability point code of the EAGLE. For example, if the EAGLE’s true point code or any capability point code is 002-002-001 and a cluster 002-002-* is configured, then the cluster 002-002-* is a home cluster.

Provisioning a home cluster causes a profound impact on network management, regarding the home cluster as well as members of the cluster. These impacts are:

Because the EAGLE is one of the accessible members of the home cluster, the EAGLE never transmits TCP or TCR messages regarding the home cluster, except for these:
- Preventive TCP – when starting to route to the cluster through an adjacent node
- Broadcast TCR – when the EAGLE starts routing on an alternate route for the entire cluster
- Back Routing TCR – to allow adjacent nodes on normal routes to route through the EAGLE, when the cluster is not accessible on the normal route
- Broadcast TCP – when the cluster (except the EAGLE itself) becomes inaccessible
If individual members are provisioned for the home cluster, the EAGLE properly generates network management messages for these nodes, except that no TFRs can be sent from those members being routed on the alternate route to the EAGLE.
Network management replies to the routeset test, and the response method generates the correct network management messages for the home cluster, its members, and unprovisioned member point codes.
When the entire home cluster is being routed on the alternate route, the EAGLE generates a full point code response method TFR reply. In such a case, the EAGLE generates only one TFR for the very first member of the cluster for which MSU is received on each signaling link to that cluster.
When the home cluster is inaccessible, the EAGLE generates one response TFP, at an interval equal to the value of the level 3 timer T8 for the members of the home cluster. If the EAGLE keeps receiving traffic for the home cluster, the EAGLE sends response TFPs for all members of the cluster.

This makes network management unreliable for the home cluster and its members.

When the normal routes, linksets LSN 1 and LSN 2, become available, the EAGLE sends a preventive TFP for destination 002-002-005 to node 002-002-002, and starts sending messages to destination 002-002-005 and cluster 002-002-* using linkset LSN 1. No preventive messages are sent for cluster 002-002-*. The EAGLE broadcasts a TFA for destination 002-002-005 and a TCA for cluster 002-002-* to all other adjacent nodes.

Node 002-002-002 sends an MSU containing the destination point code 002-002-006 on linkset LSN 1. The EAGLE responds with a response preventive TFP for destination 002-002-006 to node 002-002-002.
When linkset LSN 3 fails, node 002-002-002 sends a TFP for destination 002-002-005 to the EAGLE. The EAGLE stops using linkset LSN 1 to send traffic to destination 002-002-005, performs forced rerouting, starts the level 3 timer T11 for destination 002-002-005, and starts using linkset LSN 2 to send traffic to destination 002-002-005. The EAGLE generates a preventive TFP for destination 002-002-005 to node 002-002-003. When the level 3 timer T11 for destination 002-002-005 expires, TFRs for destination 002-002-005 are broadcast to nodes 002-002-003 and 001-001-001. Destination 002-002-005 is restricted.
Node 002-002-002 sends an MSU containing the destination point code 002-002-005 on linkset LSN 1. The EAGLE responds with a response preventive TFP for destination 002-002-005 to node 002-002-002, because no member of a home cluster is allowed to route messages back to the EAGLE.
When linkset LSN 1 fails, the EAGLE stops using linkset LSN 1 to send traffic to cluster 002-002-*, performs forced rerouting, starts the level 3 timer T11 for cluster 002-002-*, and starts using linkset LSN 2 to send traffic to cluster 002-002-*. Cluster 002-002-* is restricted. No preventive or broadcast messages are sent, and no member of the cluster is allowed to send messages back to the EAGLE.
Node 001-001-001 sends an MSU containing the destination point code 002-002-006. The EAGLE responds with a response TFR for destination 002-002-006 to node 001-001-001. The MSU is routed on linkset LSN 2.
Node 001-001-001 sends an MSU containing the destination point code 002-002-005. The EAGLE responds with a response TFR for destination 002-002-005 to node 001-001-001. The MSU is routed on linkset LSN 2.
Node 001-001-001 sends an MSU containing the destination point code 002-002-007 and receives no response. The MSU is routed on linkset LSN 2.
When linkset LSN 2 fails, destination 002-002-005 and cluster 002-002-* are prohibited. The EAGLE broadcasts a TFP for destination 002-002-005 to node 001-001-001.
Node 001-001-001 sends an MSU containing the destination point code 002-002-007. The EAGLE responds with a TFP for destination 002-002-007 to node 001-001-001, and starts the level 3 timer T8 for cluster 002-002-*.
Node 001-001-001 sends an MSU containing the destination point code 002-002-006, and receives no response until the level 3 timer T8 expires.
Node 001-001-001 sends an MSU containing the destination point code 002-002-005. The EAGLE responds with a TFP for destination 002-002-005 to node 001-001-001, and starts the level 3 timer T8 for destination 002-002-005.
Node 001-001-001 sends an MSU containing the destination point code 002-002-006. After the level 3 timer T8 for cluster 002-002-* expires, the EAGLE responds with a TFP for destination 002-002-006 to node 001-001-001, and starts the level 3 timer T8 for cluster 002-002-*.