509
Under this circumstance we can configure the as-override attribute of the CE neighbor on
the VRF address-family of BGP on PE, replacing the remote as number with the global
as number, so that CE will not filter this route due to discovering its own as number.
Example:
In CE1-PE1-P-PE2-CE2 environments, as numbers of two CE are all 200, as number of
area P is 100.
After typical environment is configured, the CE1 route will be restrained on CE 2 due to
as number, the debugging messages shows:
Prefix 11.1.1.0/24 denied due to as-path contains our own AS.
Prefix 20.1.1.0/24 denied due to as-path contains our own AS
Now configure on PE2 as follows
Switch(config)# router bgp 100
Switch(config)#address-family ipv4 vrf DC1
Switch(config-router-af)#neighbor 15.1.1.70 as-override
Switch(config-router-af)#exit-address-family
The route is successfully transmitted to CE2 after refresh, on CE2 shown:
Switch#show ip bgp
BGP table version is 5, local router ID is 100.1.1.70
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 11.1.1.0/24 15.1.1.68 0 100 100 ?
*> 15.1.1.0/24 0.0.0.0 0 32768 ?
*> 20.1.1.0/24 15.1.1.68 0 100 100 ?
*> 100.1.1.0/24 0.0.0.0 0 32768 ?
Total number of prefixes 4
13.8.3.43 neighbor capability
Command: neighbor {<ip-address>|<TAG>} capability {dynamic | route-refresh}
no neighbor {<ip-address>|<TAG>} capability {dynamic | route-refresh}
Function:
Configure dynamic update between neighbors and the route refresh
capability negotiation. The “
no neighbor {<ip-address>|<TAG>} capability {dynamic |
route-refresh}
” command do not enable the specific capability negotiation
Parameter: <ip-address>
: Neighbor IP address
<TAG>
: Name of peer group
Default:
Not configure the dynamic update capability but the route refresh capability.
