Configuring Bgp Gr - HP FlexFabric 12900E Series Configuration Manual

Step
1. Enter system view.
2. Enter BGP instance view.
3. Configure a confederation
ID.
4. Specify confederation peer
sub-ASs
confederation.
Configuring confederation compatibility
If any routers in the confederation do not comply with RFC 3065, enable confederation compatibility
to allow the router to work with those routers.
To configure confederation compatibility:
Step
1. Enter system view.
2. Enter BGP instance view.
3. Enable
compatibility.

Configuring BGP GR

Graceful Restart (GR) ensures forwarding continuous when a routing protocol restarts or an
active/standby switchover occurs. Two routers are required to complete a GR process. The following
are router roles in a GR process:
•
GR restarter—Performs GR upon a BGP restart or active/standby switchover.
•
GR helper—Helps the GR restarter to complete the GR process.
A device can act as a GR restarter and GR helper at the same time.
BGP GR works as follows:
1. The BGP GR restarter and helper exchange Open messages for GR capability negotiation. If
both parties have the GR capability, they establish a GR-capable session. The GR restarter
sends the GR timer set by the graceful-restart timer restart command to the GR helper in an
Open message.
2. When an active/standby switchover occurs or BGP restarts, the GR restarter does not remove
existing BGP routes from Routing Information Base (RIB) and Forwarding Information Base
(FIB). It still uses these routes for packet forwarding, and it starts the RIB purge timer (set by the
graceful-restart timer purge-time command). The GR helper marks all routes learned from
the GR restarter as stale instead of deleting them. It continues to use these routes for packet
forwarding. During the GR process, packet forwarding is not interrupted.
3. After the active/standby switchover or BGP restart completes, the GR restarter re-establishes a
BGP session to the GR helper. If the BGP session fails to be established within the GR timer
advertised by the GR restarter, the GR helper removes the stale routes.
4. If the BGP session is established, routing information is exchanged for the GR restarter to
retrieve route entries and for the GR helper to recover stale routes.
Command
system-view
bgp
as-number
instance-name
[ multi-session-thread ]
confederation id as-number
confederation
in the
as-number-list
Command
system-view
bgp as-number
instance-name
[ multi-session-thread ]
confederation
confederation nonstandard
instance
[
]
peer-as
[ instance
]
283
Remarks
N/A
N/A
By default, no confederation ID is
configured.
By default, no confederation peer
sub-ASs are specified.
Remarks
N/A
N/A
By default, confederation
compatibility is disabled.