Configuring bgp as number substitution, Configuration prerequisites, Configuration procedure – H3C Technologies H3C SR8800 User Manual

Page 287: Displaying and maintaining mpls l3vpn, Resetting bgp connections

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Configuring BGP AS number substitution

Configuration prerequisites

Before you configure BGP AS number substitution, complete the following tasks:

Configure basic MPLS L3VPN

Ensure CEs at different sites to have the same AS number

Configuration procedure

When CEs at different sites have the same AS number, configure the BGP AS number substitution function

to avoid route loss.
With the BGP AS number substitution function, when a PE advertises a route to a CE of the specified peer,
if an AS number identical to that of the CE exist in the AS_PATH of the route, it will be replaced with that

of the PE before the route is advertised.
To configure the BGP AS number substitution function:

Step Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enter BGP view.

bgp as-number N/A

3.

Enter BGP VPN instance view. ipv4-family vpn-instance

vpn-instance-name

N/A

4.

Enable the BGP AS number
substitution function.

peer { ip-address | group-name }
substitute-as

Disabled by default

NOTE:

For information about the peer {

ip-address | group-name } substitute-as command, see Layer 3—IP

Routing Command Reference.

Displaying and maintaining MPLS L3VPN

Resetting BGP connections

When BGP configuration changes, you can use the soft reset function or reset BGP connections to make

new configurations take effect. Soft reset requires that BGP peers have route refreshment capability

(supporting Route-Refresh messages).

Step Command Remarks

1.

Perform a soft reset of the BGP
connections in a specific VPN

instance.

refresh bgp vpn-instance vpn-instance-name
{ ip-address | all | external | group

group-name } { export | import }

Available in user view

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