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Failover of the Service PICs

The PIC failover procedure for the packet gateway assures service continuity in case of a service PIC failure. The packet gateway architecture provides both a 1:1 redundancy model and a 1:N redundancy model for service PICs.

In the 1:1 redundancy model, there is one primary service PIC and one secondary service PIC that acts as a backup. If the primary service PIC fails, the Routing Engine allocates the secondary service PIC, and the software switches over to the secondary service PIC. The PGCP process continues to provide the PGCP services as if the service PIC has restarted. All states and sessions are lost, but new calls are accepted. When the failed service PIC recovers, it does not take over from the redundant PIC.

In the 1:N redundancy model, you can define one PIC as the secondary of many primary PICs. In this model, after the secondary PIC becomes active, all other primary PICs are left without a secondary PIC. Even when the primary PIC recovers, it does not become a redundant PIC to all of the primary PICs. A recovered primary PIC can replace only the same secondary PIC that previously replaced it. This functionality means that administrative involvement is usually required after a failover event happens.

Procedure in Case of Service PIC Failure

If a service PIC fails, the following procedure takes place:

  1. Active calls are lost.
  2. The PG notifies the PGC of the failure using an FO/904 ServiceChange message.
  3. The PG receives an acknowledgment for the FO/904 message from the PGC.
  4. The redundant service PIC (rsp) mechanism allocates the secondary PIC and makes the secondary PIC the new primary PIC.
  5. The new primary PIC establishes the IPC connection to the PGCP process on the routing engine.
  6. The PGCP process issues an RS/902 registration message to the PGC.
  7. The PGCP process receives an acknowledgment of the registration message from the PGC.
  8. The PG is ready to accept and process new H.248 commands.

Configuring the Packet Gateway for PIC Redundancy

To configure PIC failover, you configure a redundancy services PIC (rsp) interface that specifies which service PIC is the primary PIC and which service PIC is the secondary PIC. In the service set configuration for the PGCP service, the service set points to the rsp interface as the next-hop service interface.

Configuring the Redundancy Services PIC (rsp) Interface

To configure, create a redundancy services PIC (rsp) interface, and specify the primary and secondary service PIC and the inside and outside service domains.

Step-by-Step Procedure

To configure the rsp interface:

  1. Configure the interface, and enter edit mode for the interface.
    [edit]
    user@host#edit interfaces rsp1
  2. Specify the service PIC that is to be the primary PIC.
    [edit interfaces rsp1]
    user@host#set redundancy-options primary sp-1/2/0
  3. Specify the service PIC that is to be the secondary PIC.
    [edit interfaces rsp1]
    user@host#set redundancy-options secondary sp-1/3/0
  4. Configure a logical unit and specify the protocol family.
    [edit interfaces rsp1]
    user@host#set unit 10 family inet
  5. Set the service domain of the logical unit to inside. This unit number must match the unit number of the inside service interface configured in the service set.
    [edit interfaces rsp1]
    user@host#set unit 10 service-domain inside
  6. Configure another logical unit and specify the protocol family.
    [edit interfaces rsp1]
    user@host#set unit 20 family inet
  7. Set the service domain of the logical unit to outside. This unit number must match the unit number of the outside service interface configured in the service set.
    [edit interfaces rsp1]
    user@host#set unit 20 service-domain outside

Configuring the Service Set for Redundant Service PICS

When you configure your service set, specify the rsp interface as the next-hop service.

Step-by-Step Procedure

To configure a service set for redundancy:

  1. Create a service set configuration.
    [edit services]
    user@host#edit service-set pgcp-svc-set
  2. Configure service set as a next-hop service set.
    [edit services service-set pgcp-svc-set]
    user@host#edit next-hop-service
  3. Specify the rsp interface to the inside network. This unit number must match the unit number of the inside service domain configured in the rsp interface.
    [edit services service-set pgcp-svc-set next-hop-service]
    user@host#set inside-service-interface rsp1.10
  4. Specify the rsp interface to the outside network. This unit number must match the unit number of the outside service domain configured in the rsp interface.
    [edit services service-set pgcp-svc-set next-hop-service]
    user@host#set outside-service-interface rsp1.20

Manually Switching from the Primary PIC to the Secondary PIC

Purpose

Manually switch from the primary PIC to the secondary PIC.

Action


user@host> request interface rsp1 switchover 
request succeeded

Manually Reverting from the Secondary PIC to the Primary PIC

Purpose

Manually revert from the secondary PIC to the primary PIC.

Action


user@host> request interface rsp1 revert 
request succeeded

Displaying the Status of the Redundant Service PICs

Purpose

Display the status of the redundant service PICs.

Action


user@host> show interface redundancy rsp1 
Interface  State            Last change  Primary    Secondary  Current status
rsp1       On primary     00:25:18        sp-1/2/0    sp-1/3/0        both up

Related Topics

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