Which of the following commands is used to verify the link-local, global unicast, and multicast addresses of an IPv6 router?
- show ipv6 neighbors (only link-local addresses)
- show ipv6 route
- show ipv6 protocols
- show ipv6 interface
The show ipv6 interface command is used to verify the link-local, global unicast, and multicast addresses assigned to an IPv6-enabled router interface. The show ipv6 interface command displays information regarding that interface, such as the physical state, MTU, and IPv6 enable/disable state.
A partial output of the show ipv6 interface command on an IPv6-enabled router named rtrA is as follows:
In the given sample output, you can see that the Fa0/1 interface of rtrA has the link-local address FE80::6339:7BFF:FE5D:A031/64 and the global unicast address 2001:7067:90D1:1::1. The global unicast address is not in EUI-64 format because when the ipv6 address command was issued, the eui64 keyword was not used. If EUI-64 format had been specified with the eui64 keyword, the global unicast address would have been 2001:7067:90D1:1:6339:7BFF:FE5D:A031.
An IPv6-enabled interface has not only a link-local and global unicast address, but also one or more multicast addresses. A multicast address is an IPv6 address that has the prefix FF00::/8. These addresses are assigned to interfaces of different nodes such that they appear as a logical group. This implies that when a packet is destined for a multicast address, that packet is delivered to all the interfaces that have the same multicast address. The various multicast groups are as follows:
FF02::1 Indicates the group of all the nodes on the local segment
FF02::2 Indicates the group of all the routers on the local segment
FF02::1:FF00:0/104 Indicates a solicited-node multicast group for every unicast or anycast address assigned to the interface
You can also notice in the sample output that the Fa0/1 interface belongs to three multicast groups: FF02::1, FF02::2, and FF02::1:FF5D:A031. The first two multicast groups refer to the all-host and all-router multicast groups, respectively. The third group, FF02::1:FF5D:A031, is the solicited-node multicast address. This address is created for every unicast or anycast address. A solicited-node multicast address is determined by assigning the least significant 24 bits of the unicast address to the least significant 24 bits of the FF02::1:FF00:0 address.
The show ipv6 neighbors command displays the link-local /global unicast addresses of the neighbors, including other information such as state and the next-hop interface.
The show ipv6 route command is used to view the IPv6 routing table on the router. This command displays the prefixes, administrative distance, metric, and next-hop addresses for various IPv6 networks.
The show ipv6 protocols command is used to view the active routing protocols for IPv6 on the router. This command shows the interfaces, redistribution status, and summarization status about each of the routing protocols enabled on the router.
Layer 3 Technologies
Identify IPv6 addressing and subnetting