Answers: IPv6 Addressing with OSPFv3 – 2

This #CCNA lab features IPv6 addressing and OSPFv3. As always, the requirements in the lab give you straightforward requirements. Create your own answer first! My answer sits here below the fold.

Answers

Figure 1: Three Router with Unicast IPv6 Addresses

Example 4: R1 Config

ipv6 unicast-routing
!
interface GigabitEthernet0/1
 ipv6 address 2000::1/64
 ipv6 ospf 15 area 0
!
interface GigabitEthernet0/2
 ipv6 address 3000::1/64
 ipv6 ospf 15 area 0
!
ipv6 router ospf 15
 router-id 1.1.1.1

Example 5: R2 Config

ipv6 unicast-routing
!
interface GigabitEthernet0/1
 ipv6 address 2500::1/64
 ipv6 ospf 15 area 0
!
interface GigabitEthernet0/2
 ipv6 address 2000::2/64 
 ipv6 ospf 15 area 0
!
ipv6 router ospf 15
 router-id 2.2.2.2

Example 6: R3 Config

ipv6 unicast-routing
!
interface GigabitEthernet0/1
 ipv6 address 2500::2/64
 ipv6 ospf 15 area 0
!
interface GigabitEthernet0/2
 ipv6 address 3500::1/64 
 ipv6 ospf 15 area 0
!
ipv6 router ospf 15
 router-id 3.3.3.3

 Commentary

You can think of this lab as having two parts: enabling IPv6 addressing, and then adding OSPFv3 as the routing protocol. To help you see those pieces, Example 4 (for router R1) shows in bold the lines related to IPv6 address configuration. Then, Example 5 (for router R2) shows in bold the lines related to the OSPFv3 configuration. Basically, all three routers have very similar configuration, so to make it easier to find, R1 (Example 4) bolds the addressing details, and R2 (Example 5) bolds the routing protocol details.

IPv6 Addressing and Routing

First, examine the configuration related to enabling IPv6 routing globally. Cisco IOS routers do not route IPv6 by default; the ipv6 unicast-routing global configuration mode command enables IPv6 routing.

Next, look for the various ipv6 address commands and compare those to the figure. Note that each interface in the figure has a matching interface in the answers, with the IPv6 address implied from the figure configured. For example, the top of the figure shows IPv6 prefix 3000::/64, with ::1 beside R1’s G0/2 interface. That interface shows an ipv6 address 3000::1/64 command that configures the IPv6 address and enables IPv6 on the interface.

OSPFv3

Finally, to complete the configuration, OSPFv3 has been enabled, with all interfaces in area 0, as follows:

• All three routers create the OSPFv3 process, with process ID 50 (ipv6 ospf router 15), and with an obvious router ID (router-id value), in the last few lines of each example.
• All interfaces include the ipv6 ospf 15 area 0 subcommand, enabling that OSPFv3 process on each interface.

Note that while the lab asked us to configure using process ID 15, and to set the router ID, those items do include a few easy mistakes. First, note that if you followed the lab literally, the initial configuration had no IPv4 configuration, so OSPFv3 would require the explicit configuration of a router ID, because none of the routers have an IPv4 address to use to create the OSPFv3 router ID. Second, while all four routers used the same OSPFv3 process ID (15), did not have to all use that number as the