300
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
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP instance view.
bgp
as-number
[
instance
instance-name
]
N/A
3.
Enable confederation
compatibility.
confederation nonstandard
By default, confederation
compatibility is disabled.
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.
5.
Both the GR restarter and the GR helper start the End-Of-RIB marker waiting timer.
The End-Of-RIB marker waiting time is set by the
graceful-restart timer wait-for-rib
command. If routing information exchange is not completed within the time, the GR restarter
does not receive new routes. The GR restarter updates the RIB with the BGP routes already
learned, and removes the aged routes from the RIB. The GR helper removes the stale routes.
6.
The GR restarter quits the GR process if routing information exchange is not completed within
the RIB purge timer. It updates the RIB with the BGP routes already learned, and removes the
aged routes.
Follow these guidelines when you configure BGP GR:
•
The End-Of-RIB indicates the end of route updates.
•
The maximum time to wait for the End-of-RIB marker configured on the local end is not
advertised to the peer. It controls the time for the local end to receive updates from the peer.
Содержание HPE FlexNetwork 7500 series
Страница 505: ...493 Connector N A ...
