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Configuring the as-path attribute – H3C Technologies H3C S7500E Series Switches User Manual

Page 245

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8-11

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.

Follow these steps to configure the AS-PATH attribute:

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 maximum

number of times the local

AS number can appear

in routes from the

peer/peer group

peer { group-name | ip-address }

allow-as-loop [ number ]

Optional

By default, the local AS

number can not appear in

routes from a peer/peer

group.

Configure the

AS_PATH

attribute

Disable BGP from

considering the

AS_PATH during best

route selection

bestroute as-path-neglect

Optional

By default, BGP considers

AS_PATH during best

route selection.