Siemens S223, S323 Graceful Restart, Configures the router to consider the MED in choosing

User Manual	UMN:CLI
SURPASS hiD 6615 S223/S323 R1.5

To compare MED values on the exchange of path information between Confederation Peers, use the following command.

Command	Mode	Description
bgp bestpath med confed [miss-		Configures the router to consider the MED in choosing
ing-as-worst]
	Router	a path from among the paths on the exchange of in-
bgp bestpath med missing-as-
		formation between confederation peers.
worst [confed]

To ignore MED values of paths on the exchange of information between confederation peers, use the following command.

Command		Mode	Description
no bgp bestpath med	confed
[missing-as-worst]		Router	Ignores MEDs of paths on the exchange of their infor-
			mation between confederation peers.
no bgp bestpath med missing-
as-worst [confed]

i

If there are several equal paths, one of them has no MED value. Because this path is considered as “zero” without MED value, it will be chosen the best path. But the path would be the worst one if it has no MED value after missing-as-worstis set.

After missing-as-worstparameter is configured in the system, the path will be recog- nized as the worst path without MED value.

10.1.2.5Graceful Restart

Graceful restart allows a router undergoing a restart to inform its adjacent neighbors and peers of its condition. The restarting router requests a grace period from the neighbor or peer, which can then cooperate with the restarting router. With a graceful restart, the re- starting router can still forward traffic during the restart period, and convergence in the network is not disrupted. The restart is not visible to the rest of the network, and the re- starting router is not removed from the network topology.

The main benefits of graceful restart are uninterrupted packet forwarding and temporary suppression of all routing protocol updates. Graceful restart thus allows a router to ex- change path information with the neighboring router.

To configure graceful restart specifically for BGP, use the following command.

Command	Mode	Description
bgp graceful-restart	Router	Sets to use graceful restart in BGP protocol.
no bgp graceful-restart		Disables the restart time value setting.

Therefore, 2 options of the time can be used to speed up routing convergence by its peer in case that BGP doesn’t come back after a restart.

A50010-Y3-C150-2-7619 323