Introduction
As defined in RFC 2283, a BGP speaker has capability of carrying routing information for multiple network layer protocols (e.g., IPv6, IPX, etc..). In this configuration example, we are routing IPv6 traffic over preestablished IPv4 EBGP connection.
Requirements
- Understanding on BGP
- IPv6 Addressing Scheme
Background
In this document, interface Fast Ethernet [0/0] of routers R1 and R2 are establishing EBGP peering. The two routers are in two different autonomous systems 100 and 200. The loopback interface (loopback 10) is assigned with IPv6 address and it is required to advertise these addresses over IPv4 EBGP peers. In the process it is important to set the IPv6 Next-Hop, in this scenario a route-map is configured to set the Next-Hop [command set ipv6 next-hop] .Or if you don’t want to use IPv6 addresses on the direct link, one has to configure a tunnel to have a valid and reachable ipv6 Next-Hop.
Note: All configurations is tested in a lab environment on Cisco 2811 router running IOS C2800NM-ADVENTERPRISEK9, Version 12.4(15)T14.
Topology Diagram
Configuration
Router R1Router R2
hostname R1
ip cef ipv6 unicast-routing
interface Loopback10 no ip address ipv6 address 2011:ABC:12E:121::1/64 ipv6 enable
interface FastEthernet0/0 ip address 17.17.17.1 255.255.255.0 duplex auto speed auto ipv6 address 2011::1/64 ipv6 enable
router bgp 100 bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 17.17.17.2 remote-as 200 neighbor 17.17.17.2 ebgp-multihop 5
address-family ipv4 neighbor 17.17.17.2 activate no auto-summary no synchronization network 17.17.17.1 mask 255.255.255.255 exit-address-family
address-family ipv6 neighbor 17.17.17.2 activate neighbor 17.17.17.2 route-map IPv6-NextHop out network 2011:ABC:12E:121::/64 exit-address-family
route-map IPv6-NextHop permit 10 set ipv6 next-hop 2011::1
end | hostname R2
ip cef ipv6 unicast-routing
interface Loopback10 no ip address ipv6 address 3011:ABC:12E:122::1/64 ipv6 enable
interface FastEthernet0/0 ip address 17.17.17.2 255.255.255.0 duplex auto speed auto ipv6 address 2011::2/64 ipv6 enable
router bgp 200 bgp router-id 2.2.2.2 bgp log-neighbor-changes neighbor 17.17.17.1 remote-as 100 neighbor 17.17.17.1 ebgp-multihop 5
address-family ipv4 neighbor 17.17.17.1 activate no auto-summary no synchronization network 17.17.17.2 mask 255.255.255.255 exit-address-family
address-family ipv6 neighbor 17.17.17.1 activate neighbor 17.17.17.1 route-map IPv6-NextHop out network 3011:ABC:12E:122::/64 exit-address-family
route-map IPv6-NextHop permit 10 set ipv6 next-hop 2011::2 end |
Verification
On Router R1
R1#show ipv6 route
IPv6 Routing Table - 6 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route, M - MIPv6
I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
D - EIGRP, EX - EIGRP external
C 2011::/64 [0/0]
via ::, FastEthernet0/0
L 2011::1/128 [0/0]
via ::, FastEthernet0/0
C 2011:ABC:12E:121::/64 [0/0]
via ::, Loopback10
L 2011:ABC:12E:121::1/128 [0/0]
via ::, Loopback10
B 3011:ABC:12E:122::/64 [20/0]
via 2011::2
L FF00::/8 [0/0]
via ::, Null0
R1#show bgp ipv6 unicast
BGP table version is 3, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2011:ABC:12E:121::/64:: 0 32768 i
*> 3011:ABC:12E:122::/64 2011::2 0 0 200 i
As seen from the above output, the IPv6 prefix 3011:ABC:12E:122::/64 is being learn by Router R1.
R1#ping ipv6
Target IPv6 address: 3011:ABC:12E:122::1
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands? [no]: y
Source address or interface: 2011:ABC:12E:121::1
UDP protocol? [no]:
Verbose? [no]:
Precedence [0]:
DSCP [0]:
Include hop by hop option? [no]:
Include destination option? [no]:
Sweep range of sizes? [no]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3011:ABC:12E:122::1, timeout is 2 seconds:
Packet sent with a source address of 2011:ABC:12E:121::1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/0 ms
References
Implementing Multiprotocol BGP for IPv6
Cisco IOS IPv6 Command Reference
IPv6 Tunnel through an IPv6 Network
Cisco: IP Version 6 (IPv6) Support Page
