Summary
- A single VPNv4 BGP session between the two ASBRs exchange control information.
- A dedicated interface per each VRF for forwarding traffic for the VRF.
- Packets are forwarded unlabelled in the inter-AS link.
- More scalable than Option A since there is no per-VRF BGP session.
Initial Configurations
AS 1 Routers
PE1
!
hostname PE1
vrf definition A
rd 1:1
!
address-family ipv4
route-target export 1:1
route-target import 1:1
exit-address-family
!
vrf definition B
rd 1:2
!
address-family ipv4
route-target export 1:2
route-target import 1:2
exit-address-family
!
mpls label protocol ldp
!
interface Loopback0
ip address 11.11.11.11 255.255.255.255
ip ospf 1 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 10.11.12.11 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
interface GigabitEthernet2
vrf forwarding A
ip address 172.16.1.1 255.255.255.252
no shutdown
!
interface GigabitEthernet3
vrf forwarding B
ip address 172.16.1.5 255.255.255.252
no shutdown
!
router ospf 1
router-id 11.11.11.11
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 1
bgp router-id 11.11.11.11
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 13.13.13.13 remote-as 1
neighbor 13.13.13.13 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 13.13.13.13 activate
neighbor 13.13.13.13 send-community extended
exit-address-family
!
address-family ipv4 vrf A
redistribute connected
neighbor 172.16.1.2 remote-as 65101
neighbor 172.16.1.2 activate
exit-address-family
!
address-family ipv4 vrf B
redistribute connected
neighbor 172.16.1.6 remote-as 65201
neighbor 172.16.1.6 activate
exit-address-family
!
mpls ldp router-id Loopback0
!P1
!
hostname P1
!
mpls label protocol ldp
!
interface Loopback0
ip address 12.12.12.12 255.255.255.255
ip ospf 1 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 10.11.12.12 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
interface GigabitEthernet2
mtu 1600
ip address 10.12.13.12 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
interface GigabitEthernet3
mtu 1600
ip address 10.12.14.12 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
router ospf 1
router-id 12.12.12.12
passive-interface default
no passive-interface GigabitEthernet1
no passive-interface GigabitEthernet2
no passive-interface GigabitEthernet3
mpls ldp sync
mpls ldp autoconfig area 0
!
mpls ldp router-id Loopback0
!RR1
!
hostname RR1
!
mpls label protocol ldp
!
interface Loopback0
ip address 13.13.13.13 255.255.255.255
ip ospf 1 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 10.12.13.13 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
router ospf 1
router-id 13.13.13.13
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 1
bgp router-id 13.13.13.13
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 11.11.11.11 remote-as 1
neighbor 11.11.11.11 update-source Loopback0
neighbor 14.14.14.14 remote-as 1
neighbor 14.14.14.14 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 11.11.11.11 activate
neighbor 11.11.11.11 send-community extended
neighbor 11.11.11.11 route-reflector-client
neighbor 14.14.14.14 activate
neighbor 14.14.14.14 send-community extended
neighbor 14.14.14.14 route-reflector-client
exit-address-family
!
mpls ldp router-id Loopback0
!ASBR1
!
hostname ASBR1
!
mpls label protocol ldp
1
interface Loopback0
ip address 14.14.14.14 255.255.255.255
ip ospf 1 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 10.12.14.14 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
router ospf 1
router-id 14.14.14.14
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 1
bgp router-id 14.14.14.14
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 13.13.13.13 remote-as 1
neighbor 13.13.13.13 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 13.13.13.13 activate
neighbor 13.13.13.13 send-community extended
exit-address-family
!
mpls ldp router-id Loopback0AS 2 Routers
PE2
!
hostname PE2
vrf definition A
rd 1:1
!
address-family ipv4
route-target export 1:1
route-target import 1:1
exit-address-family
!
vrf definition B
rd 1:2
!
address-family ipv4
route-target export 1:2
route-target import 1:2
exit-address-family
!
mpls label protocol ldp
!
interface Loopback0
ip address 21.21.21.21 255.255.255.255
ip ospf 1 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 20.11.12.11 255.255.255.0
ip ospf network point-to-point
ip ospf 1 area 0
no shutdown
!
interface GigabitEthernet2
vrf forwarding A
ip address 172.16.2.1 255.255.255.252
no shutdown
!
interface GigabitEthernet3
vrf forwarding B
ip address 172.16.2.5 255.255.255.252
no shutdown
!
router ospf 2
router-id 21.21.21.21
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 2
bgp router-id 21.21.21.21
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 23.23.23.23 remote-as 2
neighbor 23.23.23.23 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 23.23.23.23 activate
neighbor 23.23.23.23 send-community extended
exit-address-family
!
address-family ipv4 vrf A
redistribute connected
neighbor 172.16.2.2 remote-as 65102
neighbor 172.16.2.2 activate
exit-address-family
!
address-family ipv4 vrf B
redistribute connected
neighbor 172.16.2.6 remote-as 65202
neighbor 172.16.2.6 activate
exit-address-family
!
mpls ldp router-id Loopback0
!P2
!
hostname P2
!
mpls label protocol ldp
!
interface Loopback0
ip address 22.22.22.22 255.255.255.255
ip ospf 2 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 20.21.22.22 255.255.255.0
ip ospf network point-to-point
ip ospf 2 area 0
no shutdown
!
interface GigabitEthernet2
mtu 1600
ip address 20.22.23.22 255.255.255.0
ip ospf network point-to-point
ip ospf 2 area 0
no shutdown
interface GigabitEthernet3
mtu 1600
ip address 20.22.24.22 255.255.255.0
ip ospf network point-to-point
ip ospf 2 area 0
no shutdown
!
router ospf 2
router-id 22.22.22.22
passive-interface default
no passive-interface GigabitEthernet1
no passive-interface GigabitEthernet2
no passive-interface GigabitEthernet3
mpls ldp sync
mpls ldp autoconfig area 0
!
mpls ldp router-id Loopback0
!RR2
!
hostname RR2
!
mpls label protocol ldp
!
interface Loopback0
ip address 23.23.23.23 255.255.255.255
ip ospf 2 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 20.22.23.23 255.255.255.0
ip ospf network point-to-point
ip ospf 2 area 0
no shutdown
!
router ospf 1
router-id 23.23.23.23
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 2
bgp router-id 23.23.23.23
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 21.21.21.21 remote-as 2
neighbor 21.21.21.21 update-source Loopback0
neighbor 24.24.24.24 remote-as 2
neighbor 24.24.24.24 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 21.21.21.21 activate
neighbor 21.21.21.21 send-community extended
neighbor 21.21.21.21 route-reflector-client
neighbor 24.24.24.24 activate
neighbor 24.24.24.24 send-community extended
neighbor 24.24.24.24 route-reflector-client
exit-address-family
!
mpls ldp router-id Loopback0
!ASBR2
!
hostname ASBR2
!
mpls label protocol ldp
!
interface Loopback0
ip address 24.24.24.24 255.255.255.255
ip ospf 2 area 0
!
interface GigabitEthernet1
mtu 1600
ip address 20.22.24.24 255.255.255.0
ip ospf network point-to-point
ip ospf 2 area 0
no shutdown
!
router ospf 2
router-id 24.24.24.24
passive-interface default
no passive-interface GigabitEthernet1
mpls ldp sync
mpls ldp autoconfig area 0
!
router bgp 2
bgp router-id 24.24.24.24
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 23.23.23.23 remote-as 2
neighbor 23.23.23.23 update-source Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 23.23.23.23 activate
neighbor 23.23.23.23 send-community extended
exit-address-family
!
mpls ldp router-id Loopback0CE Routers
CE-A1
hostname CE-A1
interface GigabitEthernet0/0
ip address 172.16.1.2 255.255.255.252
no shut
interface Loopback0
ip address 192.168.1.1 255.255.255.255
router bgp 65101
bgp router-id 192.168.1.1
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 172.16.1.1 remote-as 1
!
address-family ipv4
network 192.168.1.1 mask 255.255.255.255
neighbor 172.16.1.1 activate
exit-address-familyCE-A2
hostname CE-A2
interface GigabitEthernet0/0
ip address 172.16.2.2 255.255.255.252
no shut
interface Loopback0
ip address 192.168.1.2 255.255.255.255
router bgp 65102
bgp router-id 192.168.1.2
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 172.16.2.1 remote-as 2
!
address-family ipv4
network 192.168.1.2 mask 255.255.255.255
neighbor 172.16.2.1 activate
exit-address-familyCE-B1
hostname CE-B1
interface GigabitEthernet0/0
ip address 172.16.1.6 255.255.255.252
no shut
interface Loopback0
ip address 192.168.2.1 255.255.255.255
router bgp 65201
bgp router-id 192.168.2.1
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 172.16.2.5 remote-as 1
!
address-family ipv4
network 192.168.2.1 mask 255.255.255.255
neighbor 172.16.2.5 activate
exit-address-familyCE-B2
hostname CE-B2
interface GigabitEthernet0/0
ip address 172.16.2.6 255.255.255.252
no shut
interface Loopback0
ip address 192.168.2.2 255.255.255.255
router bgp 65202
bgp router-id 192.168.2.2
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 172.16.2.5 remote-as 2
!
address-family ipv4
network 192.168.2.2 mask 255.255.255.255
neighbor 172.16.2.5 activate
exit-address-familyInter-AS Configuration
VRF and Interfaces
ASBR1
vrf definition A
rd 1:1
!
address-family ipv4
route-target export 1:1
route-target import 1:1
inter-as-hybrid next-hop 172.16.0.2
exit-address-family
!
vrf definition B
rd 1:2
!
address-family ipv4
route-target export 1:2
route-target import 1:2
inter-as-hybrid next-hop 172.16.0.6
exit-address-family
!
interface GigabitEthernet2
mtu 1600
no ip address
no shutdown
!
interface GigabitEthernet2.101
encapsulation dot1Q 101
vrf forwarding A
ip address 172.16.0.1 255.255.255.252
!
interface GigabitEthernet2.102
encapsulation dot1Q 102
vrf forwarding B
ip address 172.16.0.5 255.255.255.252
!ASBR2
vrf definition A
rd 1:1
!
address-family ipv4
route-target export 1:1
route-target import 1:1
inter-as-hybrid next-hop 172.16.0.1
exit-address-family
!
vrf definition B
rd 1:2
!
address-family ipv4
route-target export 1:2
route-target import 1:2
inter-as-hybrid next-hop 172.16.0.5
exit-address-family
!
interface GigabitEthernet2
mtu 1600
no ip address
no shutdown
!
interface GigabitEthernet2.101
encapsulation dot1Q 101
vrf forwarding A
ip address 172.16.0.2 255.255.255.252
!
interface GigabitEthernet2.102
encapsulation dot1Q 102
vrf forwarding B
ip address 172.16.0.6 255.255.255.252
!
Inter-AS BGP
ASBR1
router bgp 1
neighbor 172.16.0.254 remote-as 2
!
address-family vpnv4
neighbor 172.16.0.254 activate
neighbor 172.16.0.254 send-community extended
neighbor 172.16.0.254 inter-as-hybrid
exit-address-family
!
address-family ipv4 vrf A
redistribute connected
exit-address-family
!
address-family ipv4 vrf B
redistribute connected
exit-address-familyASBR2
router bgp 2
neighbor 172.16.0.253 remote-as 1
!
address-family vpnv4
neighbor 172.16.0.253 activate
neighbor 172.16.0.253 send-community extended
neighbor 172.16.0.253 inter-as-hybrid
exit-address-family
!
address-family ipv4 vrf A
redistribute connected
exit-address-family
!
address-family ipv4 vrf B
redistribute connected
exit-address-family
Verification
ASBR1
ASBR1#show bgp vpnv4 unicast vrf A
BGP table version is 19, local router ID is 14.14.14.14
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf A)
* 172.16.0.0/30 172.16.0.254 0 0 2 ?
*> 0.0.0.0 0 32768 ?
*>i 172.16.1.0/30 11.11.11.11 0 100 0 ?
*> 172.16.2.0/30 172.16.0.254 0 2 ?
*>i 192.168.1.1/32 11.11.11.11 0 100 0 65101 i
*> 192.168.1.2/32 172.16.0.254 0 2 65102 i
ASBR1#show bgp vpnv4 unicast vrf B
BGP table version is 19, local router ID is 14.14.14.14
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:2 (default for vrf B)
* 172.16.0.4/30 172.16.0.254 0 0 2 ?
*> 0.0.0.0 0 32768 ?
*>i 172.16.1.4/30 11.11.11.11 0 100 0 ?
*> 172.16.2.4/30 172.16.0.254 0 2 ?
*>i 192.168.2.1/32 11.11.11.11 0 100 0 65201 i
*> 192.168.2.2/32 172.16.0.254 0 2 65202 i
ASBR1#
ASBR1#show ip route vrf A | beg Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.0.0/30 is directly connected, GigabitEthernet2.101
L 172.16.0.1/32 is directly connected, GigabitEthernet2.101
B 172.16.1.0/30 [200/0] via 11.11.11.11, 01:01:27
B 172.16.2.0/30 [20/0] via 172.16.0.2, 01:01:27
192.168.1.0/32 is subnetted, 2 subnets
B 192.168.1.1 [200/0] via 11.11.11.11, 01:01:27
B 192.168.1.2 [20/0] via 172.16.0.2, 01:01:27
ASBR1#
ASBR1#show ip route vrf B | beg Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.0.4/30 is directly connected, GigabitEthernet2.102
L 172.16.0.5/32 is directly connected, GigabitEthernet2.102
B 172.16.1.4/30 [200/0] via 11.11.11.11, 01:09:22
B 172.16.2.4/30 [20/0] via 172.16.0.6, 01:09:22
192.168.2.0/32 is subnetted, 2 subnets
B 192.168.2.1 [200/0] via 11.11.11.11, 01:09:22
B 192.168.2.2 [20/0] via 172.16.0.6, 01:09:22
ASBR1#
ASBR1#show ip cef vrf A 192.168.1.1/32 detail
192.168.1.1/32, epoch 0, flags [rib defined all labels]
recursive via 11.11.11.11 label 23
nexthop 10.12.14.12 GigabitEthernet1 label 16-(local:18)
ASBR1#show ip cef vrf A 192.168.1.2/32 detail
192.168.1.2/32, epoch 0, flags [rib only nolabel, rib defined all labels]
dflt local label info: other/26 [0x2]
recursive via 172.16.0.2
attached to GigabitEthernet2.101
ASBR1#
ASBR1#show ip cef vrf B 192.168.2.1/32 detail
192.168.2.1/32, epoch 0, flags [rib defined all labels]
recursive via 11.11.11.11 label 24
nexthop 10.12.14.12 GigabitEthernet1 label 16-(local:18)
ASBR1#
ASBR1#show ip cef vrf B 192.168.2.2/32 detail
192.168.2.2/32, epoch 0, flags [rib only nolabel, rib defined all labels]
dflt local label info: other/24 [0x2]
recursive via 172.16.0.6
attached to GigabitEthernet2.102
ASBR1#ASBR2
ASBR2#show bgp vpnv4 unicast vrf A
BGP table version is 19, local router ID is 24.24.24.24
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf A)
*> 172.16.0.0/30 0.0.0.0 0 32768 ?
* 172.16.0.253 0 0 1 ?
*> 172.16.1.0/30 172.16.0.253 0 1 ?
*>i 172.16.2.0/30 21.21.21.21 0 100 0 ?
*> 192.168.1.1/32 172.16.0.253 0 1 65101 i
*>i 192.168.1.2/32 21.21.21.21 0 100 0 65102 i
ASBR2#
ASBR2#
ASBR2#show bgp vpnv4 unicast vrf B
BGP table version is 19, local router ID is 24.24.24.24
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:2 (default for vrf B)
*> 172.16.0.4/30 0.0.0.0 0 32768 ?
* 172.16.0.253 0 0 1 ?
*> 172.16.1.4/30 172.16.0.253 0 1 ?
*>i 172.16.2.4/30 21.21.21.21 0 100 0 ?
*> 192.168.2.1/32 172.16.0.253 0 1 65201 i
*>i 192.168.2.2/32 21.21.21.21 0 100 0 65202 i
ASBR2#
ASBR2#
ASBR2#show ip route vrf A | beg Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.0.0/30 is directly connected, GigabitEthernet2.101
L 172.16.0.2/32 is directly connected, GigabitEthernet2.101
B 172.16.1.0/30 [20/0] via 172.16.0.1, 01:04:42
B 172.16.2.0/30 [200/0] via 21.21.21.21, 01:04:42
192.168.1.0/32 is subnetted, 2 subnets
B 192.168.1.1 [20/0] via 172.16.0.1, 01:04:42
B 192.168.1.2 [200/0] via 21.21.21.21, 01:04:42
ASBR2#
ASBR2#show ip route vrf B | beg Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.0.4/30 is directly connected, GigabitEthernet2.102
L 172.16.0.6/32 is directly connected, GigabitEthernet2.102
B 172.16.1.4/30 [20/0] via 172.16.0.5, 01:11:55
B 172.16.2.4/30 [200/0] via 21.21.21.21, 01:11:55
192.168.2.0/32 is subnetted, 2 subnets
B 192.168.2.1 [20/0] via 172.16.0.5, 01:11:55
B 192.168.2.2 [200/0] via 21.21.21.21, 01:11:55
ASBR2#
ASBR2#
ASBR2#show ip cef vrf A 192.168.1.1/32 detail
192.168.1.1/32, epoch 0, flags [rib only nolabel, rib defined all labels]
dflt local label info: other/23 [0x2]
recursive via 172.16.0.1
attached to GigabitEthernet2.101
ASBR2#show ip cef vrf A 192.168.1.2/32 detail
192.168.1.2/32, epoch 0, flags [rib defined all labels]
recursive via 21.21.21.21 label 16
nexthop 20.22.24.22 GigabitEthernet1 label 16-(local:18)
ASBR2#
ASBR2#show ip cef vrf B 192.168.2.1/32 detail
192.168.2.1/32, epoch 0, flags [rib only nolabel, rib defined all labels]
dflt local label info: other/24 [0x2]
recursive via 172.16.0.5
attached to GigabitEthernet2.102
ASBR2#show ip cef vrf B 192.168.2.2/32 detail
192.168.2.2/32, epoch 0, flags [rib defined all labels]
recursive via 21.21.21.21 label 17
nexthop 20.22.24.22 GigabitEthernet1 label 16-(local:18)
ASBR2#CE-A1
CE-A1#traceroute ip 192.168.1.2 source 192.168.1.1 numeric
Type escape sequence to abort.
Tracing the route to 192.168.1.2
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.1.1 [AS 1] 1 msec 1 msec 1 msec
2 10.11.12.12 [MPLS: Labels 18/26 Exp 0] 2 msec 2 msec 2 msec
3 172.16.0.1 [AS 1] [MPLS: Label 26 Exp 0] 1 msec 1 msec 1 msec
4 172.16.0.2 [AS 1] 2 msec 1 msec 1 msec
5 20.22.24.22 [MPLS: Labels 16/16 Exp 0] 3 msec 3 msec 2 msec
6 172.16.2.1 [AS 2] [MPLS: Label 16 Exp 0] 3 msec 2 msec 2 msec
7 172.16.2.2 [AS 2] 2 msec * 3 msec
CE-A1#CE-A2
CE-A2#traceroute ip 192.168.1.1 source 192.168.1.2 numeric
Type escape sequence to abort.
Tracing the route to 192.168.1.1
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.2.1 [AS 2] 0 msec 0 msec 1 msec
2 20.21.22.22 [MPLS: Labels 18/23 Exp 0] 2 msec 1 msec 2 msec
3 172.16.0.2 [AS 2] [MPLS: Label 23 Exp 0] 1 msec 1 msec 1 msec
4 172.16.0.1 [AS 2] 1 msec 1 msec 1 msec
5 10.12.14.12 [MPLS: Labels 16/23 Exp 0] 3 msec 2 msec 3 msec
6 172.16.1.1 [AS 1] [MPLS: Label 23 Exp 0] 2 msec 2 msec 2 msec
7 172.16.1.2 [AS 1] 3 msec * 3 msec
CE-A2#CE-B1
CE-B1#traceroute 192.168.2.2 source 192.168.2.1 numeric
Type escape sequence to abort.
Tracing the route to 192.168.2.2
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.1.5 [AS 1] 0 msec 0 msec 0 msec
2 10.11.12.12 [MPLS: Labels 18/24 Exp 0] 2 msec 2 msec 1 msec
3 172.16.0.5 [AS 1] [MPLS: Label 24 Exp 0] 1 msec 1 msec 1 msec
4 172.16.0.6 [AS 1] 1 msec 1 msec 1 msec
5 20.22.24.22 [MPLS: Labels 16/17 Exp 0] 3 msec 3 msec 2 msec
6 172.16.2.5 [AS 2] [MPLS: Label 17 Exp 0] 2 msec 2 msec 2 msec
7 172.16.2.6 [AS 2] 2 msec * 2 msec
CE-B1#CE-B2
CE-B2#traceroute 192.168.2.1 source 192.168.2.2 numeric
Type escape sequence to abort.
Tracing the route to 192.168.2.1
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.2.5 [AS 2] 1 msec 0 msec 1 msec
2 20.21.22.22 [MPLS: Labels 18/24 Exp 0] 2 msec 1 msec 2 msec
3 172.16.0.6 [AS 2] [MPLS: Label 24 Exp 0] 1 msec 1 msec 1 msec
4 172.16.0.5 [AS 2] 1 msec 1 msec 2 msec
5 10.12.14.12 [MPLS: Labels 16/24 Exp 0] 2 msec 2 msec 2 msec
6 172.16.1.5 [AS 1] [MPLS: Label 24 Exp 0] 3 msec 2 msec 2 msec
7 172.16.1.6 [AS 1] 2 msec * 2 msec
CE-B2#Packet Capture on inter-AS link
Packets are sent unlabelled
The outputs below shows that the next hop address in the BGP advertisement is changed to the remote end of the link belong to the VRF when the route is imported into the VRF table.
Incoming BGP Update packet captured at ASBR1
No. Time Source Destination Protocol Length Info
19 24.339876 172.16.0.254 172.16.0.253 BGP 607 UPDATE Message, UPDATE Message, UPDATE Message, UPDATE Message, UPDATE Message, UPDATE Message, UPDATE Message
Frame 19: 607 bytes on wire (4856 bits), 607 bytes captured (4856 bits) on interface -, id 0
Interface id: 0 (-)
Interface name: -
Encapsulation type: Ethernet (1)
Arrival Time: Oct 11, 2022 10:33:46.627621000 AEST
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1665448426.627621000 seconds
[Time delta from previous captured frame: 0.000257000 seconds]
[Time delta from previous displayed frame: 0.000257000 seconds]
[Time since reference or first frame: 24.339876000 seconds]
Frame Number: 19
Frame Length: 607 bytes (4856 bits)
Capture Length: 607 bytes (4856 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:vlan:ethertype:ip:tcp:bgp]
[Coloring Rule Name: TTL low or unexpected]
[Coloring Rule String: ( ! ip.dst == 224.0.0.0/4 && ip.ttl < 5 && !pim && !ospf) || (ip.dst == 224.0.0.0/24 && ip.dst != 224.0.0.251 && ip.ttl != 1 && !(vrrp || carp))]
Ethernet II, Src: 50:00:00:04:00:01 (50:00:00:04:00:01), Dst: 50:00:00:03:00:01 (50:00:00:03:00:01)
Destination: 50:00:00:03:00:01 (50:00:00:03:00:01)
Address: 50:00:00:03:00:01 (50:00:00:03:00:01)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Source: 50:00:00:04:00:01 (50:00:00:04:00:01)
Address: 50:00:00:04:00:01 (50:00:00:04:00:01)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: 802.1Q Virtual LAN (0x8100)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 164
000. .... .... .... = Priority: Best Effort (default) (0)
...0 .... .... .... = DEI: Ineligible
.... 0000 1010 0100 = ID: 164
Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 172.16.0.254, Dst: 172.16.0.253
0100 .... = Version: 4
.... 0101 = Header Length: 20 bytes (5)
Differentiated Services Field: 0xc0 (DSCP: CS6, ECN: Not-ECT)
1100 00.. = Differentiated Services Codepoint: Class Selector 6 (48)
.... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
Total Length: 589
Identification: 0x157e (5502)
Flags: 0x40, Don't fragment
0... .... = Reserved bit: Not set
.1.. .... = Don't fragment: Set
..0. .... = More fragments: Not set
Fragment Offset: 0
Time to Live: 1
[Expert Info (Note/Sequence): "Time To Live" only 1]
["Time To Live" only 1]
[Severity level: Note]
[Group: Sequence]
Protocol: TCP (6)
Header Checksum: 0x0752 [validation disabled]
[Header checksum status: Unverified]
Source Address: 172.16.0.254
Destination Address: 172.16.0.253
Transmission Control Protocol, Src Port: 179, Dst Port: 47343, Seq: 96, Ack: 77, Len: 549
Source Port: 179
Destination Port: 47343
[Stream index: 1]
[TCP Segment Len: 549]
Sequence Number: 96 (relative sequence number)
Sequence Number (raw): 2140866061
[Next Sequence Number: 645 (relative sequence number)]
Acknowledgment Number: 77 (relative ack number)
Acknowledgment number (raw): 6723070
0101 .... = Header Length: 20 bytes (5)
Flags: 0x018 (PSH, ACK)
000. .... .... = Reserved: Not set
...0 .... .... = Nonce: Not set
.... 0... .... = Congestion Window Reduced (CWR): Not set
.... .0.. .... = ECN-Echo: Not set
.... ..0. .... = Urgent: Not set
.... ...1 .... = Acknowledgment: Set
.... .... 1... = Push: Set
.... .... .0.. = Reset: Not set
.... .... ..0. = Syn: Not set
.... .... ...0 = Fin: Not set
[TCP Flags: ·······AP···]
Window: 16308
[Calculated window size: 16308]
[Window size scaling factor: -2 (no window scaling used)]
Checksum: 0x0dd1 [unverified]
[Checksum Status: Unverified]
Urgent Pointer: 0
[SEQ/ACK analysis]
[iRTT: 0.001462000 seconds]
[Bytes in flight: 568]
[Bytes sent since last PSH flag: 549]
[Timestamps]
[Time since first frame in this TCP stream: 0.018012000 seconds]
[Time since previous frame in this TCP stream: 0.000257000 seconds]
TCP payload (549 bytes)
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 87
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 64
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 120
Label Stack: 31 (bottom)
Route Distinguisher: 1:2
MP Reach NLRI IPv4 prefix: 192.168.2.2
Path Attribute - ORIGIN: IGP
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: IGP (0)
Path Attribute - AS_PATH: 2 65202
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 10
AS Path segment: 2 65202
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 2
AS4: 2
AS4: 65202
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:2 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 2
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 87
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 64
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 120
Label Stack: 28 (bottom)
Route Distinguisher: 1:1
MP Reach NLRI IPv4 prefix: 192.168.1.2
Path Attribute - ORIGIN: IGP
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: IGP (0)
Path Attribute - AS_PATH: 2 65102
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 10
AS Path segment: 2 65102
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 2
AS4: 2
AS4: 65102
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:1 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 1
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 83
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 60
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 118
Label Stack: 28 (bottom)
Route Distinguisher: 1:1
MP Reach NLRI IPv4 prefix: 172.16.2.0
Path Attribute - ORIGIN: INCOMPLETE
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: INCOMPLETE (2)
Path Attribute - AS_PATH: 2
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 6
AS Path segment: 2
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 1
AS4: 2
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:1 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 1
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 83
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 60
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 118
Label Stack: 31 (bottom)
Route Distinguisher: 1:2
MP Reach NLRI IPv4 prefix: 172.16.2.4
Path Attribute - ORIGIN: INCOMPLETE
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: INCOMPLETE (2)
Path Attribute - AS_PATH: 2
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 6
AS Path segment: 2
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 1
AS4: 2
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:2 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 2
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 90
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 67
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 118
Label Stack: 22 (bottom)
Route Distinguisher: 1:1
MP Reach NLRI IPv4 prefix: 172.16.0.0
Path Attribute - ORIGIN: INCOMPLETE
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: INCOMPLETE (2)
Path Attribute - AS_PATH: 2
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 6
AS Path segment: 2
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 1
AS4: 2
Path Attribute - MULTI_EXIT_DISC: 0
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MULTI_EXIT_DISC (4)
Length: 4
Multiple exit discriminator: 0
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:1 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 1
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 90
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 67
Path attributes
Path Attribute - MP_REACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_REACH_NLRI (14)
Length: 33
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Next hop network address (12 bytes)
Next Hop: Empty Label Stack RD=0:0 IPv4=172.16.0.254
Number of Subnetwork points of attachment (SNPA): 0
Network layer reachability information (16 bytes)
BGP Prefix
Prefix Length: 118
Label Stack: 27 (bottom)
Route Distinguisher: 1:2
MP Reach NLRI IPv4 prefix: 172.16.0.4
Path Attribute - ORIGIN: INCOMPLETE
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: ORIGIN (1)
Length: 1
Origin: INCOMPLETE (2)
Path Attribute - AS_PATH: 2
Flags: 0x40, Transitive, Well-known, Complete
0... .... = Optional: Not set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: AS_PATH (2)
Length: 6
AS Path segment: 2
Segment type: AS_SEQUENCE (2)
Segment length (number of ASN): 1
AS4: 2
Path Attribute - MULTI_EXIT_DISC: 0
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MULTI_EXIT_DISC (4)
Length: 4
Multiple exit discriminator: 0
Path Attribute - EXTENDED_COMMUNITIES
Flags: 0xc0, Optional, Transitive, Complete
1... .... = Optional: Set
.1.. .... = Transitive: Set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: EXTENDED_COMMUNITIES (16)
Length: 8
Carried extended communities: (1 community)
Route Target: 1:2 [Transitive 2-Octet AS-Specific]
Type: Transitive 2-Octet AS-Specific (0x00)
0... .... = IANA Authority: Allocated on Standard Action, Early Allocation or Experimental Basis
.0.. .... = Transitive across AS: Transitive
Subtype (AS2): Route Target (0x02)
2-Octet AS: 1
4-Octet AN: 2
Border Gateway Protocol - UPDATE Message
Marker: ffffffffffffffffffffffffffffffff
Length: 29
Type: UPDATE Message (2)
Withdrawn Routes Length: 0
Total Path Attribute Length: 6
Path attributes
Path Attribute - MP_UNREACH_NLRI
Flags: 0x80, Optional, Non-transitive, Complete
1... .... = Optional: Set
.0.. .... = Transitive: Not set
..0. .... = Partial: Not set
...0 .... = Extended-Length: Not set
.... 0000 = Unused: 0x0
Type Code: MP_UNREACH_NLRI (15)
Length: 3
Address family identifier (AFI): IPv4 (1)
Subsequent address family identifier (SAFI): Labeled VPN Unicast (128)
Withdrawn routes (0 bytes)
Outputs from ASBR1
ASBR1#show bgp vpnv4 unicast all 192.168.1.2 255.255.255.255
BGP routing table entry for 1:1:192.168.1.2/32, version 29
Paths: (1 available, best #1, table A)
Advertised to update-groups:
13
Refresh Epoch 1
2 65102
172.16.0.254 (via default) from 172.16.0.254 (24.24.24.24)
Origin IGP, localpref 100, valid, external, best
Extended Community: RT:1:1
mpls labels in/out 26/28
rx pathid: 0, tx pathid: 0x0
Updated on Oct 11 2022 00:33:46 UTC
ASBR1#
ASBR1#show ip route vrf A 192.168.1.2 255.255.255.255
Routing Table: A
Routing entry for 192.168.1.2/32
Known via "bgp 1", distance 20, metric 0
Tag 2, type external
Last update from 172.16.0.2 00:06:25 ago
Routing Descriptor Blocks:
* 172.16.0.2, from 172.16.0.254, 00:06:25 ago
opaque_ptr 0x7F18C7B565E8
Route metric is 0, traffic share count is 1
AS Hops 2
Route tag 2
MPLS label: none
ASBR1#
ASBR1#
ASBR1#show bgp vpnv4 unicast all 192.168.2.2 255.255.255.255
BGP routing table entry for 1:2:192.168.2.2/32, version 31
Paths: (1 available, best #1, table B)
Advertised to update-groups:
13
Refresh Epoch 1
2 65202
172.16.0.254 (via default) from 172.16.0.254 (24.24.24.24)
Origin IGP, localpref 100, valid, external, best
Extended Community: RT:1:2
mpls labels in/out 24/31
rx pathid: 0, tx pathid: 0x0
Updated on Oct 11 2022 00:33:46 UTC
ASBR1#
ASBR1#show ip route vrf B 192.168.2.2 255.255.255.255
Routing Table: B
Routing entry for 192.168.2.2/32
Known via "bgp 1", distance 20, metric 0
Tag 2, type external
Last update from 172.16.0.6 00:06:42 ago
Routing Descriptor Blocks:
* 172.16.0.6, from 172.16.0.254, 00:06:42 ago
opaque_ptr 0x7F18C7B56210
Route metric is 0, traffic share count is 1
AS Hops 2
Route tag 2
MPLS label: none
ASBR1#Summary
- Packets are sent as unlabelled IP packets in the Inter-AS link.
- A link per VRF (Similar to Option A).
- A single BGP session between ASBRs to exchange VPNv4 prefixes for all the VRFs (Similar to Option B).
- Next-hop is changed to VRF remote end when imported into VRF.