Enabling GR for BGP4+ Peers

After graceful restart (GR) is enabled for BGP4+ peers specified on a BGP4+ speaker, the BGP4+ speaker can negotiate the GR capability with these peers and establish BGP4+ connections with them if negotiation succeeds.

Usage Scenario

A BGP4+ restart causes re-establishment of all the involved peer relationships, resulting in traffic interruption. Enabling GR globally can prevent traffic interruption. However, this will disconnect all the BGP4+ peer relationships on a device and cause the device to re-negotiate the GR capability with these peers, which affects all the BGP4+-dependent services running on the live network. To prevent this problem, you can enable GR on a BGP4+ speaker for specified BGP4+ peers so that the BGP4+ speaker negotiates the GR capability only with the specified peers. If negotiation succeeds, BGP4+ connections are established between the BGP4+ speaker and specified peers.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run bgp as-number

    The BGP view is displayed.

  3. Run peer ipv6-address capability-advertise graceful-restart

    GR is enabled for a specified peer. After this command is run, the device will advertise the GR capability to the specified peer.

    If a specified peer does not support GR, run the peer ipv6-address local-graceful-restart enable command instead to enable local GR for the specified peer.

  4. (Optional) Run peer ipv6-address graceful-restart timer restart time-value

    The maximum duration is set for the specified peer to reestablish its BGP4+ peer relationship with the device. After the command is run, the device will advertise the maximum duration to the specified peer.

    If a specified peer does not support GR, run the peer ipv6-address local-graceful-restart timer restart restart-time command instead to set the maximum duration for the device to wait for its BGP4+ peer relationship to be reestablished with the specified peer.

  5. (Optional) Run peer ipv6-address graceful-restart peer-reset

    The device is enabled to use the GR mode to reset the BGP4+ connection with the specified peer.

    Currently, BGP4+ does not support dynamic capability negotiation. Therefore, each time a BGP4+ capability is changed or a new BGP4+ capability is enabled, a BGP4+ speaker tears down the existing sessions with the affected peers and renegotiates BGP4+ capabilities with these peers. For example, a BGP4+ speaker has established a BGP IPv6 unicast peer relationship with a peer, and the IPv6 service is running properly. A change of BGP4+ capability causes the BGP IPv6 unicast peer relationship to be reestablished, affecting the normal running of the IPv6 service. To address this issue, run the peer ipv6-address graceful-restart peer-reset command.

  6. (Optional) Run peer ipv6-address graceful-restart timer wait-for-rib time-value

    The maximum duration is set for the device to wait for the End-of-RIB flag from the specified peer.

    If a specified peer does not support GR, run the peer ipv6-address local-graceful-restart timer wait-for-rib wfrtime command instead to set the maximum duration.

  7. Run commit

    The configuration is committed.

Verifying the Configuration

  • Run the display bgp ipv6 peer verbose command to check the BGP4+ GR status.
  • Run the display bgp graceful-restart status command to check the GR information on the BGP4+ speaker.
  • Run the display bgp local-graceful-restart status command to check information about local GR on the BGP4+ speaker.
Parent Topic: BGP4+ Configuration
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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