3Com S7906E - Switch, Configuration Manual

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1-9
To do… Use the command… Remarks
Configure the
default MED
value
default med med-value
Optional
0 by default.
Enable the
comparison of the
MED of routes
from different ASs
compare-different-as-med
Optional
Not enabled by default
Enable the
comparison of the
MED of routes
from each AS
bestroute compare-med
Optional
Not enabled by default
Configure
the MED
attribute
Enable the
comparison of the
MED of routes
from
confederation
peers
bestroute med-confederation
Optional
Not enabled by default
Configuring the Next Hop Attribute
You can use the peer next-hop-local command to specify the local router as the next hop of routes
sent to a MBGP iBGP peer/peer group. If load balancing is configured, the router specifies itself as the
next hop of route advertisements to the multicast iBGP peer/peer group regardless of whether the peer
next-hop-local command is configured.
In a “third party next hop" network, that is, the local router has two multicast eBGP peers in a broadcast
network, the router does not specify itself as the next hop of routing information sent to the eBGP peers
unless the peer next-hop-local command is configured.
Follow these steps to specify the router as the next hop of routes sent to a peer/peer group:
To do… Use the command… Remarks
Enter system view system-view
—
Enter BGP view bgp as-number
—
Enter IPv4 MBGP address family
view
ipv4-family multicast
—
Specify the router as the next hop
of routes sent to a peer/peer
group
peer { group-name | ip-address }
next-hop-local
Optional
By default, the next hop
of routes sent to a MBGP
eBGP peer/peer group is
the advertising router,
while that of routes sent
to a MBGP iBGP
peer/peer group is not.
Configuring the AS-PATH Attribute
In general, MBGP checks whether the AS_PATH attribute of a route from a peer contains the local AS
number. If yes, it discards the route to avoid routing loops.