IPv6 EIGRP

Similar in operation to IPv4 EIGRP.
- Transport via protocol 88 to unicast and multicast FF02::A
Not enabled by default with EIGRP classic mode.
- ‘no shutdown’ needed under process.
Enabled on all IPv6 links in named mode.
- ‘address-family ipv6 unicast <vrf> autonomous system <#>’
- process not shutdown by default.
- To exclude EIGRP link:
  - ‘af-interface Y’
  - ‘shutdown’
IPv4 Router-ID needed.

The topology above is running DMVPN Phase 3. R5 is the hub and R1-3 are the spokes. The topology is running IPv4 as the underlay/transport, and then each router has a loopback with IPv4 being advertised into EIGRP AS 1. In addition, each router has an IPv6 address that’s running over the top of IPv4 mGRE/DMVPN. There is no routing protocol yet running IPv6, which is what will be completed with EIGRP.

First step is to turn on EIGRP on each router with the below commands. It will be the same for all:

In addition there was another link added to R5 that is being advertised into EIGRP AS 100. After entering the config above the adjacencies began flapping up and down. Discovered the below command was missing under tunnel 0 on all routers:

Now adjacencies are stable and on spokes we’re seeing a route from the extra link/network coming from R5, outside of the DMVPN domain.

Now on R1 an additional loopback was added with an IPv6 address that’s being advertised into EIGRP AS 100. On R3 when viewing the routing table we’re not seeing it, but we are in R5. This is because split horizon needs to be disabled.