Prev Question
Next Question

Which of the following commands is used to verify the link-local, global unicast, and multicast addresses of
an IPv6 router?

A. show ipv6 neighbors (only link-local addresses)

B. show ipv6 route

C. show ipv6 protocols

D. show ipv6 interface

Explanation:
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.
Objective:
Layer 3 Technologies
Sub-Objective:
Identify IPv6 addressing and subnetting
References:
Cisco IOS IPv6 Command Reference > show ipv6 eigrp topology through show ipv6 nat statistics > show
ipv6 interface
Cisco IOS IPv6 Command Reference > show ipv6 nat translations through show ipv6 protocols > show ipv6
neighbors
Cisco IOS IPv6 Command Reference > show ipv6 nat translations through show ipv6 protocols > show ipv6
protocols
Cisco > Products & Services > Cisco IOS and NX-OS Software > Cisco IOS Technologies > IPv6 > Product
Literature > White Papers > Cisco IOS IPv6 Multicast Introduction
Cisco > IPv6 Implementation Guide, Release 15.2M&T > Implementing IPv6 Multicast

Prev Question
Next Question

Leave a Reply

Your email address will not be published. Required fields are marked *