This lab has some repetitive configuration elements for EIGRPv6. Check out the original lab first, and then come here to check out your answers. The main task in this case: Get EIGRP working for IPv6 in a three router pod.

Answers

Figure 1: Three Router Triangle with Unicast IPv6 Addresses

Example 4: R1 Config

Example 5: R2 Config

Example 6: R3 Config

Commentary

EIGRP for IPv6 is very similar to its IPv4 variant, it still uses the bandwidth and delay of the route path to calculate metric and still maintains topology and neighbor tables. There are, however, some unique parts of the configuration that are different from legacy EIGRP configuration. First, EIGRP for IPv6 uses an interface style of configuration (i.e. using ipv6 eigrp commands). Second, unlike EIGRP for IPv4, EIGRP for IPv6 requires either an interface on the device to be configured with an IPv4 address OR that the router-id is statically configured as part of the EIGRP for IPv6 configuration; this is because an IPv4 style of router-id is still used.

For this lab, the bandwidth of the link between R2 and R3 is altered to make it less preferred over its faster alternative. This change will affect the routing tables of R2 and R3; specifically, it will affect how many routes R2 will have for the 2001::/64 network and how many routes R3 will have for the 2000::/64 network.

All three routers use the ipv6 router eigrp 20 command, which creates an EIGRPv6 process on each router, with ASN 20, a number which must match on the three routers. Then each router has a command like R1’s eigrp router-id 1.1.1.1 to define the EIGRP router ID. Note that as shown, this router has no IPv4 addresses at all, so the router ID must be explicitly configured as shown here.

Then look at all the interfaces on all three routers. Each interface has an ipv6 eigrp 20 subcommand, enabling the use of the ASN 20 EIGRPv6 process on that interface.

Finally, look at R2’s G0/1 interface and R3’s G0/2 interface. They both use the bandwidth 100000 subcommand, setting the speed down to match the actual link speed. As a result, EIGRP on R2 and R3 will choose routes that run through R1 rather than directly between R2 and R3. Also, note that this bandwidth 100000 command is not actually needed, because the bandwidth setting on router LAN interfaces will adjust to the negotiated speed assuming no bandwidth command is configured on the interface.