3com 8807 Reference Guide

C

HAPTER

 38: MBGP M

ULTICAST

 E

XTENSION

 C

ONFIGURATION

 C

OMMANDS

[3Com-bgp] ipv4-family multicast

 

[3Com-bgp-af-mul] default local-preference 180 

default med med-value

IPv4 multicast sub-address family view

med-value: MED value, in the range of 0 to 4294967295. By default, it is 0.

Use the default med command to configure system MED value.

Use the display bgp multicast group command to restore the default value.

Multi-exit discriminator (MED) attribute is the external metric for a route. Unlike 
local precedence attribute, MED is exchanged, between ASs, and one it enters an 
AS, it does not leave the AS. MED attribute is used in best route selection. When a 
router running BGP travels through different external peers and get the routes 
with identical destination, but different next-hop addresses, it selects these routes 
according to their MED values. The route with smaller MED value will be selected 
as the external AS route if other attributes are the same.

# Configure system MED value as 25.

<SW8800> system-view

 

System View: return to User View with Ctrl+Z.

 

[SW8800] bgp 100

 

[3Com-bgp] ipv4-family multicast

 

[3Com-bgp-af-mul] default med 25 

display bgp multicast group [ group-name ]

Any view

group-name: Peer group. If no peer group is specified, the information about all 
peer groups will be displayed.

Use the display bgp multicast group command to view the information about 
peer groups.