H3C Technologies H3C SR8800 - Manual (Page 239)

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Configuring the AS-PATH attribute
Permitting 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.
Disabling 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.
Specifying 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.
To specify a fake AS number for a peer/peer group:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view. bgp as-number N/A
3. Specify a fake AS number for a
peer/peer group. peer { group-name | ip-address }
fake-as as-number
Optional
Not specified by default
NOTE:
This command is only applicable to an EBGP peer or peer group.