See attached Physical TOPO.
CE(s) AS is 65100
PE(s) AS is 65501
CE1 vrf 100 (vrf lite) peered to PE1 vrf 100
CE2 vrf 100 (vrf lite) peeredto PE2 vrf 10.
CE1 is advertising 11.100.0.0/24
1. At PE1; we see the route. Since CE1 originated the route; its AS_PATH is set to CE1 AS.
RP/0/RSP1/CPU0:PE1-ASR9K-AG04-1#show bgp vrf 100 ipv4 unicast
BGP VRF 100, state: Active
BGP Route Distinguisher: 1:100
VRF ID: 0x60000001
BGP router identifier 21.1.101.1, local AS number 65501
BGP table state: Active
Table ID: 0xe0000010 RD version: 93478
BGP main routing table version 93478
Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:100 (default for vrf 100)
*> 11.100.0.0/24 121.1.201.1 0 0 65100 ?
*>i12.100.0.0/24 21.6.101.1 0 100 0 ?
*> 21.1.201.1/32 0.0.0.0 0 32768 ?
2. At PE2; we see the route. Sent to PE2 (via a route reflector not shown).
RP/0/RSP1/CPU0:PE2-ASR9K-AG04-2#show bgp vrf 100 ipv4 unicast
BGP VRF 100, state: Active
BGP Route Distinguisher: 1:100
VRF ID: 0x60000002
BGP router identifier 21.2.101.1, local AS number 65501
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000011 RD version: 91134
BGP main routing table version 91134
BGP NSR Initial initsync version 4294967295 (Not Reached)
Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:100 (default for vrf 100)
*>i11.100.0.0/24 21.1.101.1 0 100 0 65100 ?
Here is where it gets sticky, and I believe I'm missing some rule set of MP-BGP. Unless we set as-override at PE2, PE2 will never send an update to CE2. My belief in the scenerio was that PE2 would sent the advertisement but CE2 should dampen it unless it unless we set it to allow our own AS in , allow-as in.