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:
- 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.
- 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.
- 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.
- 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.
