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    Configuring Session DPC Redundancy

    The MobileNext Broadband Gateway chassis includes a number of session Dense Port Concentrators (DPCs) (we recommend at least two). Each session DPC consists of two services PICs: services PIC 0 and services PIC 1. The session DPCs anchor control plane functions on the broadband gateway.

    Before you begin configuring session DPC redundancy on a broadband gateway chassis, you should have done the following:

    • Configured the chassis of the broadband gateway
    • Configured the session DPCs

    The session DPCs support 1:1 redundancy. That is, the PICs in the session DPCs are configured in a one-to-one correspondence with their backups. So, for example, if the PIC0 in the session DPC in FPC slot 0 is paired with PIC0 in the session DPC in FPC slot 1, one PIC will back up the other PIC. These pairs are called aggregate multiservices (ams-) PICs and the member interfaces are called members of the AMS (mams-). However, the standby device is lost as a services PIC and all services are supplied by the active PIC. In this case, the session PICs associate mams-0/0/0 and mams-1/0/0 as active and standby pairs. You also configure units for AMS interfaces, and these are used for AAA and charging.

    Note: You cannot configure a services PIC logical interface (ms-0/0/0.0, for example) if you also make the same logical interface part of an AMS (mams-0/0/0.0, for example). This configuration will not commit.

    You configure the AMS member interface that is the preferred backup. You can configure more than one AMS group, but each must have the 1:1 redundancy, of course.

    To configure AMS group membership and redundancy actions for a pair of session DPCs on a broadband gateway:

    1. Configure the session DPC redundancy pair called ams0 so that PIC 1 of the session DPC in FPC slot 0 is backed-up by FPC slot 5 PIC 1.
      [edit interfaces]user@host# set ams0 load-balancing-options member-interface mams-4/1/0 user@host# set ams0 load-balancing-options member-interface mams-5/1/0

      Note: The load-balancing-options keyword has nothing to do with load balancing. When used for mobility, session DPCs automatically load-balance sessions.

    2. Configure the preferred backup for ams0 so that FPC 4 PIC 1 is the active session DPC and FPC 5 PIC 1 is the backup.
      [edit interfaces]user@host# set ams0 load-balancing-options high-availability-options many-to-one preferred-backup mams-5/1/0

      Note: The many-to-one option is still used for 1:1 redundancy in this case.

    3. Configure the logical interfaces (units) for ams0 so that unit 0 and unit 1 are available for AAA and charging uses.
      [edit interfaces]user@host# set ams0 unit 1 family inet user@host# set ams0 unit 2 family inet

      Note: You do not have to assign an IP address.

    4. Configure the failure parameters for the members on ams0.
      [edit interfaces]user@host# set ams0 load-balancing-options member-interface-options redistribute-all-traffic enable-rejoin

      Note: The enable-rejoin option is the only option currently supported for redistribute-all-traffic. If you configure the redistribute-all-traffic statement, you cannot also configure the drop-member-traffic statement on the same AMS group.

    Published: 2011-11-22