Configuring Bundle Protection Group Ports

Bundle Protection groups enable APS protection of one bundle residing on a working circuit of an APS group port by another bundle residing on the protection circuit of that APS group port. Bundle protection groups apply to MLPPP as well, and are configured the same way. The following examples show the process to configure BPGrp on ASAP MDAs to provide an APS protection for an IMA/MLPPP bundle.

First, two ASAP MDAs must be configured.

config# card 3
    config>card# mda 2
    config>card>mda# mda-type m4-choc3-as-sfp
    config>card>mda# no shutdown
    config>card>mda# exit
    config>card# exit
    config# card 10
    config>card# mda 2
    config>card>mda# mda-type m4-choc3-as-sfp
    config>card>mda# no shutdown
    config>card>mda# exit

Configure an APS group with working and protection circuits on the ASAP MDAs.

config# port aps-1
    — config>port# aps
    — config>port>aps# working-circuit 3/2/1
    — config>port>aps# protect-circuit 10/2/1
    — config>port>aps# exit
    — config>port# no shutdown

Create eight ATM DS1 channels on the APS group.

config>port>aps# 
    — config>port# sonet-sdh
    — config>port>sonet-sdh# path sts1-1
    — config>port>sonet-sdh>path# no shutdown
    — config>port>sonet-sdh>path# exit
    — config>port>sonet-sdh# exit
    — config>port# tdm
    — config>port>tdm#
    — config>port>tdm# ds3 1
    — config>port>tdm>ds3# channelized ds1
    — config>port>tdm>ds3# no shutdown
    — config>port>tdm>ds3# exit
    — config>port>tdm# ds1 1.1
    — config>port>tdm>ds1# channel-group 1
    — config>port>tdm>ds1>channel-group# encap-type atm 
    — config>port>tdm>ds1>channel-group# no shutdown
    — config>port>tdm>ds1>channel-group# exit
    — config>port>tdm# ds1 1.8
    — config>port>tdm>ds1# channel-group 1
    — config>port>tdm>ds1>channel-group# encap-type atm 
    — config>port>tdm>ds1>channel-group# no shutdown
    — config>port>tdm>ds1>channel-group# exit

Next, configure an IMA-type/MLPPP-type BPGrp with working and protection bundles on working and protection circuits of aps-1 and members the created DS1s (this creates 2 IMA bundles, one on working and one on protection circuit):

config# port bpgrp-ima-1
    — config>port# multilink-bundle
    — config>port>multilink-bundle# working-bundle bundle-ima-1/1.1
    — config>port>multilink-bundle# protect-bundle bundle-ima-2/1.1
    — config>port>multilink-bundle# member aps-1.1.1.1
    — config>port>multilink-bundle# member aps-1.1.2.1
    — config>port>multilink-bundle# member aps-1.1.3.1
    — config>port>multilink-bundle# member aps-1.1.4.1
    — config>port>multilink-bundle# member aps-1.1.5.1
    — config>port>multilink-bundle# member aps-1.1.6.1
    — config>port>multilink-bundle# member aps-1.1.7.1
    — config>port>multilink-bundle# member aps-1.1.8.1
    — config>port>multilink-bundle# exit
    — config>port>multilink-bundle# no shutdown
    — config>port>multilink-bundle# exit
    — config>port# no shutdown

Finally, a service can be configured on this bundle using the BPGrp ID (for example, an ATM VC 0/32 SAP would be: sap bpg-ima-1:0/32).

Configuration Notes and Guidelines:

Any configuration on a BPGrp applies to both the working and protection bundle.
Working and protection bundles can be shutdown individually.
Services cannot be configured on a BPGrp until at least one member link has been configured.
The published switchover times for bundle protection groups on the router are dependent on the far end being able to recover from cell loss within that time. To ensure this, the following recommendations are given:
- The BPGrp link activation timer should be configured to a value small enough to allow a quick recovery from any IMA failure occurring during the switchover. A recommended value is 1 second.
- The ADM that terminates APS should support standard APS switchover time requirements.
- The far end IMA/MLPPP links must be able to tolerate cell loss during APS switchover without bringing links down. This includes, for example, a combination of link activation/deactivation and appropriate configuration of TDM/SONET debounce timers.
- Because of the temporary cell loss during the APS switchover, the far end IMA/MLPPP experiences a misalignment between individual links within an IMA/MLPPP group. The far end IMA/MLPPP group must support fast-realignment of links without having to bring the links down. The router synchronizes the IMA/MLPPP streams the far end receives between switchovers in an effort to cause the least amount of misalignment.
- To increase the BPGrp robustness, it is recommended to provision more IMA/MLPPP links than is required and set the minimum links and max bandwidth parameters to the number of required links. This type of configuration is required on the far end as well.