Configuring the as-path attribute – H3C Technologies H3C SecPath F1000-E User Manual
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If you have configured BGP load balancing on a BGP router, the router will set it as the next hop for routes
sent to an IBGP peer/peer group regardless of whether the peer next-hop-local command is configured.
To configure the next hop attribute:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp as-number
N/A
3.
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 router sets it as
the next hop for routes sent to
an EBGP peer/peer group,
but does not set it as the next
hop for routes sent to an IBGP
peer/peer group.
Configuring the AS-PATH attribute
1.
Permit local AS number to appear in routes from a peer/peer group.
In general, BGP checks whether the AS_PATH attribute of a route from a peer contains the local AS
number. If so, it discards the route to avoid routing loops.
To permit local AS number to appear in routes from a peer/peer group and specify the
appearance times.
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp as-number
N/A
3.
Permit local AS number to
appear in routes from a
peer/peer group and specify
the appearance times.
peer { group-name | ip-address }
allow-as-loop [ number ]
Optional.
By default, the local AS
number is not allowed.
2.
Disable BGP from considering AS_PATH during best route selection.
To disable BGP from considering AS_PATH during best route selection:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp as-number
N/A
3.
Disable BGP from considering
AS_PATH during best route
selection.
bestroute as-path-neglect
Optional.
By default, BGP considers
AS_PATH during best route
selection.
3.
Specify a fake AS number for a peer/peer group.
When Router A in AS 2 is moved to AS 3, you can configure Router A to specify a fake AS number
of 2 for created connections to EBGP peers/peer groups. In this way, these EBGP peers still think
Router A is in AS 2 and need not change their configurations. This feature ensures uninterrupted
BGP services.