BGP as the PE – CE Protocol Notes
BGP as the PE – CE Protocol
When R1 sends an update to R4 with R5’s information, the update will include AS 50 in the AS-PATH. R4 will see 50 in the AS-PATH and drop the update. There are two solutions that will allow R4 to accept the update.
– osi
-> PE side solution
– allowas-in
-> CE side solution
R1(config)# ip vrf c1b1
rd 1:1
route-target both 1:1
int s0/0
ip vrf forwarding c1b1
router bgp 100
neighbor 3.3.3.3 remote-as 100
neighbor 3.3.3.3 update-source lo0
address-family vpnv4 unicast
neighbor 3.3.3.3 activate
address-familty ipv4 vrf c1b1
neighbor 14.0.0.1 remote-as 50
neighbor 14.0.0.1 as-override
-> PE side solution
R4(config)# router bgp 50
neighbor 14.0.0.1 remote-as 100
neighbor 14.0.0.1 allowas-in
-> CE side solution
