Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Chapter 5 BGP Configuration
5-17
AS 100
EBGP
IBGP
IBGP
IBGP
EBGP
EBGP
AS 65002
AS 65003
AS 65004
AS 200
Figure 5-15
Confederation network diagram
From the perspective of a non-confederation speaker, it needs not know sub-ASs in the
confederation. The ID of the confederation is the number of the AS. In the above figure,
AS200 is the confederation ID.
The deficiency of confederation is: when changing an AS into a confederation, you
need to reconfigure your routers, and the topology will be changed.
In large-scale BGP networks, both route reflector and confederation can be used.
5.1.6 BGP GR
Note:
For GR (Graceful Restart) information, refer to
BFD
GR Configuration
.
1) To establish a BGP session with a peer, a BGP GR Restarter sends an OPEN
message with GR capability to the peer.
2)
Upon receipt of this message, the peer is aware that the sending router is capable
of Graceful Restart, and sends an OPEN message with GR Capability to the GR
Restarter to establish a GR session. If neither party has the GR capability, the
session established between them will not be GR capable.
3)
The GR session between the GR Restarter and its peer goes down when the GR
Restarter restarts BGP. The GR capable peer will mark all routes associated with
the GR Restarter as stale. However, during the configured GR Time, it still uses
these routes for packet forwarding, ensuring that no packet will be lost when
routing information from its peer is recollected.
