IPv6 Tunneling over IPv4
Topology
Initial configuration
The initial configuration consist basically of IPv4 interfaces and routing between R1 and R3:
R1 Configuration:
interface Loopback0
ip address 1.1.1.1 255.255.255.255
ip ospf 10 area 0
!
interface Ethernet0/0
ip address 172.16.10.1 255.255.255.252
ip ospf 10 area 0
router ospf 10
R2 Configuration:
R2#
interface Ethernet0/0
ip address 172.16.10.2 255.255.255.252
ip ospf 10 area 0
!
interface Ethernet0/1
ip address 172.16.20.2 255.255.255.252
ip ospf 10 area 0
router ospf 10
R3 Configuration:
interface Loopback0
ip address 3.3.3.3 255.255.255.255
ip ospf 10 area 0
!
interface Ethernet0/0
ip address 172.16.20.1 255.255.255.252
ip ospf 10 area 0
!
router ospf 10Create Tunnel to encapsulate IPv6
- Tunnel configuration:
R1:
interface Tunnel0
no ip address
tunnel source Loopback0
tunnel destination 1.1.1.1
R2:
interface Tunnel0
no ip address
tunnel source Loopback0
tunnel destination 3.3.3.3- Activate IPv6 and configure OSPFv3 on the interface Tunnel:
On R1 and R2:
Tunnel is up, we can enable IPv6 and configure OSPFv3 routing on the tunnel:
interface Tunnel0
ipv6 enable
ipv6 ospf 20 area 0
We can verify that OSPFv3 adjacency between Tunnel interfaces:
R3#show ipv6 ospf neighbor
OSPFv3 Router with ID (3.3.3.3) (Process ID 20)
Neighbor ID Pri State Dead Time Interface ID Interface
1.1.1.1 0 FULL/ - 00:00:36 10 Tunnel0
R3#show ipv6 ospf interface
Tunnel0 is up, line protocol is up
Link Local Address FE80::A8BB:CCFF:FE01:3000, Interface ID 11
Area 0, Process ID 20, Instance ID 0, Router ID 3.3.3.3
Network Type POINT_TO_POINT, Cost: 1000
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Graceful restart helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 3
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 1.1.1.1
Suppress hello for 0 neighbor(s)- Create an interface Lo1 with IPv6 address and advertise it through OSPFv3:
On R1:
interface Loopback1
no ip address
ipv6 address 2001::1/64
ipv6 enable
ipv6 ospf 20 area 0
end
On R2:
interface Loopback1
no ip address
ipv6 address 2003::3/64
ipv6 enable
ipv6 ospf 20 area 0
endVerification and Test:
On Router R1:
R1#show ipv6 route
IPv6 Routing Table - default - 4 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, la - LISP alt
lr - LISP site-registrations, ld - LISP dyn-eid, a - Application
C 2001::/64 [0/0]
via Loopback1, directly connected
L 2001::1/128 [0/0]
via Loopback1, receive
O 2003::3/128 [110/1000]
via FE80::A8BB:CCFF:FE01:3000, Tunnel0
L FF00::/8 [0/0]
via Null0, receive
R1#ping 2003::3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2003::3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 msWhen pinging from R1 to R2, we performed a Wireshark capture:
We can see that the IPv6 packet is encapsulated inside IPv4 packet (through GRE) and the tunnel source and destination are the outer IP.
