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Specifying a fake AS number for a peer or 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 or 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 or 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 or
peer group.
peer
{
group-name
|
ip-address
}
fake-as
as-number
Optional.
Not specified by default.
This command is only
applicable to an EBGP peer
or peer group.
Removing private AS numbers from updates to a peer or peer group
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Configure BGP to remove private AS
numbers from the AS_PATH attribute of
updates to a peer or peer group.
peer
{
group-name
|
ip-address
}
public-as-only
By default, BGP updates
carry private AS numbers.
Ignoring the first AS number of EBGP route updates
Typically, BGP checks the AS_PATH attribute of a route update received from a peer. If the first AS number
is not that of the BGP peer, the BGP router discards the route update.
To ignore the first AS number of EBGP route updates:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Configure BGP to ignore the first AS
number of EBGP route updates.
ignore-first-as
By default, BGP checks the
first AS number of EBGP
route updates.
Tuning and optimizing BGP networks
Configuration prerequisites
BGP connections must be created.
