3com 8807 참조 가이드

Use the default med command to configure the default system metric.

Use the undo default med command to restore the default metric of the system.

Multi-Exit Discriminators (MED) attribute is the external metric of a route. Different 
from local preference, MED is exchanged between ASs. However, this attribute is 
non-transitive. When a router running BGP gets routes with the same destination 
address but different next hops from different external peers, it selects the route 
with the smallest MED as the optimum route, provided that all other conditions 
are the same.

# Routers RTA and RTB belong to AS100 and router RTC belongs to AS200. RTC is 
the peer of RTA and RTB. So the MED of RTA can be configured as 25 to allow RTC 
to select the route transmitted by RTB first.

[3Com-bgp] default med 25 

BGP view

None

Use the default-route imported command to allow BGP to import the default 
routes of other routing protocols.

Use the undo default-route imported command to filter their default routes 
when BGP is importing other routing protocols.

When BGP is importing other routing protocols, BGP does not import their default 
routes by default.

# Configure a static default route.

<SW8800> system-view  

 

[SW8800] ip route-static 0.0.0.0 0.0.0.0 NULL 0 

# Import static routes into BGP.

[SW8800] bgp 100

 

[3Com-bgp] import-route static 

# Find out that no static default route is imported into BGP.