In this lab, you will configure global unicast addresses, rely on link local addresses only on some links, and use OSPFv3 to learn routes to the global unicast prefixes. Ready to check your work in this long-ish lab? If not, go back and review the requirements, then do a quick check here.
Answers
Figure 1: Three Router Triangle without Unicast IPv6 Addresses
Example 4: R1 Config
ipv6 unicast-routing ! interface GigabitEthernet0/1 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/2 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/3 ipv6 address 2001:DB8:1:1::1/64 ipv6 ospf 50 area 0 ! ipv6 router ospf 50 router-id 1.1.1.1
Example 5: R2 Config
ipv6 unicast-routing ! interface GigabitEthernet0/1 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/2 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/3 ipv6 address 2001:DB8:2:2::2/64 ipv6 ospf 50 area 0 ! ipv6 router ospf 50 router-id 2.2.2.2
Example 6: R3 Config
ipv6 unicast-routing ! interface GigabitEthernet0/1 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/2 ipv6 enable ipv6 ospf 50 area 0 ! interface GigabitEthernet0/3 ipv6 address 2001:DB8:3:3::3/64 ipv6 ospf 50 area 0 ! ipv6 router ospf 50 router-id 3.3.3.3
Commentary
All three routers have very similar configuration. Take your time working through the details of the lab.
IPv6 Address and Routing
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, to enable IPv6 on each interface, you have two general options. First, you can enable IPv6 and configure a specific unicast IPv6 address using the ipv6 address command. However, to enable IPv6 so that the router creates link local addresses, but does not have any other unicast addresses, use the ipv6 enable command. Scan the answers and you will see the ipv6 enable command on all router interfaces that connect to another router, as requested.
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 50), and with an obvious router ID (router-id value), in the last few lines of each example.
- All interfaces include the ipv6 ospf 50 area 0 subcommand, enabling that OSPFv3 process on each interface.
Note that while the lab asked us to configure using process ID 50, 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 a IPv4 address to use to create the OSPFv3 router ID. Second, while all four routers used the same OSPFv3 process ID (50), that did not have to all use that number. The lab did not specific, and they do not have to match.