Cisco IPv6 Static Address Configuration

Posted on May 30, 2012 by Sean Wilkins in Cisco with 0 Comments

Overview

Once you have a basic understanding of IPv6, the next logical step on Cisco equipment is to test out the different capabilities that exist within Cisco equipment and IOS. This article takes a look at the configuration of IPv6 addressing on a Cisco IOS device.

Cisco IPv6 Static Address Configuration

IPv6 is a little different from IPv4 in that multiple IPv6 addresses can exist on a single network interface; this can include an Aggregatable Unicast Address, Link-Local Unicast address, and/or anycast address. The next few sections review the configuration of these different address types.

Configuring Unicast Addresses

There are two common address types that are assigned to each IPv6 interface; this includes an Aggregatable Unicast address and a Link-Local address. An Aggregatable Unicast address is allowed to be globally routed and operates similarly to a public IPv4 address.

An Aggregatable Unicast address can be configured in a number of ways. This article goes over the ways to statically address an IPv6 interface, which includes either specifying the whole IPv6 address and prefix-length or by using a prefix and using EUI-64. Table 1 shows the steps that are required to configure an Aggregatable Unicast address, using both a completely manual configuration and by using EUI-64.

Table 1 – IPv6 Aggregatable Unicast Address Configuration

1 Enter global configuration mode router#configure terminal
2 Enter interface configuration mode router(config)#interface interface
3 Configure the interface with a manual Aggregatable Unicast address router(config-if)#ipv6 address address/prefix-length
OR
3 Configure the interface with an Aggregatable Unicast address using EUI-64. This method uses the prefix and the Interface ID to develop the complete IPv6 address to use. router(config-if)#ipv6 address address-prefix eui-64

A Link-Local address is used to communicate between devices that share the same link; these addresses are only allowed to be used on the local link and are not routed. Link-Local addresses will automatically be configured using the interface identifier (typically the MAC address) when IPv6 is enabled on an interface or the Link-Local address can be manually configured. Table 2 shows the steps that are required to manually configure a Link-Local address.

Table 2 – IPv6 Link-Local Address Configuration

1 Enter global configuration mode router#configure terminal
2 Enter interface configuration mode router(config)#interface interface
3 Configure the interface with a Link-Local address router(config-if)#ipv6 address address link-local

Configuring Anycast Addresses

The concept of an Anycast address did not exist within IPv4 and is intended to be (along with additional use of Multicast) a replacement for some of the capabilities of IPv4 broadcast addresses. An Anycast address is intended to be configured on the interface of multiple network devices that provide the same services (i.e. the subnet gateway, DNS server or other server). When a client uses the address, the network will direct it only to the closest device assigned the address to the client. Table 3 shows the steps that are required to configure an Anycast address on an interface.

Table 3 – IPv6 Anycast Address Configuration

1 Enter global configuration mode router#configure terminal
2 Enter interface configuration mode router(config)#interface interface
3 Configure the interface with an Anycast address router(config-if)#ipv6 address address/prefix-length anycast

Summary

While there are certainly a number of differences between IPv4 and IPv6 other than the obvious address length, what should be kept in mind is that the majority of the fundamentals are very similar and anyone familiar with IPv4 should be able to transition with a little research and practice. Hopefully the contents of this article make the static configuration of IPv6 address on a Cisco IOS device a little easier.

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