R2511-HP MSR Router Series Layer 3 - IP Routing Configuration Guide(V5)

211
Step Command Remarks
3. Configure a confederation ID.
confederation id as-number Not configured by default.
4. Specify peering sub ASs in the
confederation.
confederation peer-as
as-number-list
Not configured by default.
Configuring confederation compatibility
If some other routers in the confederation do not comply with RFC 3065, you must enable confederation
compatibility to allow the router to work with those routers.
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter BGP view.
bgp as-number N/A
3. Enable compatibility with
routers not compliant with
RFC 3065 in the
confederation.
confederation nonstandard
Optional.
Not enabled by default.
Configuring BGP GR
Graceful Restart (GR) ensures the continuity of packet forwarding when BGP restarts or an
active/standby switchover occurs:
• GR restarter—Graceful restarting router. It must be GR capable.
• GR helper—A neighbor of the GR restarter. It helps the GR restarter to complete the GR process.
NOTE:
A
n MSR router can act as only a GR helper.
Following is a GR process:
1. A BGP GR restarter and Helper exchange Open messages with GR capability. If both parties have
the GR capability, the session established between them is GR capable.
2. When an active/standby switchover occurs on the GR restarter, the GR restarter does not remove
existing route entries; it still uses these routes for packet forwarding. The GR helper marks all routes
learned from the GR restarter as stale, instead of deleting them; it still uses these routes for packet
forwarding. During the GR process, packet forwarding is not interrupted.
3. After the active/standby switchover is completed, the GR restarter reestablishes a GR session with
the GR helper. If no BGP session is established within the interval set with the graceful-restart timer
restart command, the GR helper removes the stale routes.
4. If a BGP session is established, routing information is exchanged between them for the GR restarter
to retrieve route entries, and for the GR helper to recover stale routes. You can control the routing
information exchange interval by configuring 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; instead, it updates its routing table and forwarding table with the BGP routes already
learned to complete BGP routing convergence. The GR helper then removes the state routes.
Follow these guidelines when you configure BGP GR: