Run OSPFv3 between two routers and advertise their LANs

Tasks

1. Enable IPv6 routing and address the interfaces, with readable link-local addresses.
2. Start OSPFv3 process 1 with a manual router ID on each router.
3. Enable OSPFv3 in area 0 on the LAN and transit interfaces.
4. Make the LAN interfaces passive and the transit link point-to-point.
5. Verify the adjacency, the routes and end-to-end reachability.

Solution

1. 1Routing and addresses on R1R1

   ipv6 unicast-routing
   !
   interface GigabitEthernet0/0/0
    ipv6 address fe80::1 link-local
    ipv6 address 2001:db8:acad:10::1/64
    no shutdown
   !
   interface GigabitEthernet0/0/1
    ipv6 address fe80::1 link-local
    ipv6 address 2001:db8:acad:ff::1/64
    no shutdown

   In production the transit link would use a /127. A /64 keeps the lab easy to read.

2. 2OSPFv3 process on R1R1

   router ospfv3 1
    router-id 1.1.1.1
    address-family ipv6 unicast
     passive-interface GigabitEthernet0/0/0
    exit-address-family

   The router ID is a 32-bit number. With no IPv4 address on the box, OSPFv3 cannot pick one by itself and will not run.

3. 3Enable OSPFv3 on R1's interfacesR1

   interface GigabitEthernet0/0/0
    ospfv3 1 ipv6 area 0
   !
   interface GigabitEthernet0/0/1
    ospfv3 network point-to-point
    ospfv3 1 ipv6 area 0

   Point-to-point skips the DR election and its wait time on a link with only two routers.

4. 4Same on R2R2

   ipv6 unicast-routing
   !
   interface GigabitEthernet0/0/0
    ipv6 address fe80::2 link-local
    ipv6 address 2001:db8:acad:20::1/64
    ospfv3 1 ipv6 area 0
    no shutdown
   !
   interface GigabitEthernet0/0/1
    ipv6 address fe80::2 link-local
    ipv6 address 2001:db8:acad:ff::2/64
    ospfv3 network point-to-point
    ospfv3 1 ipv6 area 0
    no shutdown
   !
   router ospfv3 1
    router-id 2.2.2.2
    address-family ipv6 unicast
     passive-interface GigabitEthernet0/0/0
    exit-address-family

Verify

R1# show ospfv3 neighbor
          OSPFv3 1 address-family ipv6 (router-id 1.1.1.1)

Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
2.2.2.2           0   FULL/  -        00:00:35    6               GigabitEthernet0/0/1

R1# show ospfv3 interface brief
Interface    PID   Area            AF         Cost  State Nbrs F/C
Gi0/0/1      1     0               ipv6       1     P2P   1/1
Gi0/0/0      1     0               ipv6       1     DR    0/0

R1# show ipv6 route ospf | begin ^O
O   2001:DB8:ACAD:20::/64 [110/2]
     via FE80::2, GigabitEthernet0/0/1

R1# ping 2001:db8:acad:20::1 source GigabitEthernet0/0/0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001:DB8:ACAD:20::1, timeout is 2 seconds:
Packet sent with a source address of 2001:DB8:ACAD:10::1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

Mistakes people make

• No router ID on a router without IPv4 addresses. IOS logs that OSPFv3 could not pick a router ID and no adjacency forms.
• Forgetting ipv6 unicast-routing. OSPFv3 config is accepted but nothing is routed.
• Hello or dead timers, area or Instance ID different on the two ends. The subnet does not have to match in OSPFv3.
• An MTU mismatch on the link. Neighbors stall in EXSTART or EXCHANGE, as in OSPFv2.
• Making the transit interface passive by mistake. The prefix is advertised, but no adjacency forms over it.

On other platforms

ipv6 router ospf 1
 router-id 1.1.1.1
 passive-interface GigabitEthernet0/0/0
!
interface GigabitEthernet0/0/0
 ipv6 ospf 1 area 0
interface GigabitEthernet0/0/1
 ipv6 ospf network point-to-point
 ipv6 ospf 1 area 0

set routing-options router-id 1.1.1.1
set protocols ospf3 area 0.0.0.0 interface ge-0/0/1.0 interface-type p2p
set protocols ospf3 area 0.0.0.0 interface ge-0/0/0.0 passive