IPv6 Addressing

IPv6 Address Sources

IPv6 Address Sources

IPv6 addressing sources provide a flexible methodology for assigning addresses to VLAN interfaces on the switch. Options include:

■stateless IPv6 autoconfiguration on VLAN interfaces includes:

•link-local unicast addresses

•global unicast addresses

■stateful IPv6 address configuration using DHCPv6

■static IPv6 address configuration

You can combine stateless, stateful, and static IP addressing methods on the switch as needed, according to the needs in your network. For example, if your network includes only one VLAN, you may need only stateless autocon­ figuration of link-local addresses, although you could also use the static IPv6 method. (DHCPv6 does not configure link-local addresses.) Where routed traffic is used, you will also need global unicast addressing, either through stateless autoconfiguration or the other listed methods.

Stateless Address Autoconfiguration (SLAAC)

On the switches covered by this guide, stateless address autoconfiguration (SLAAC) generates link-local unicast and global unicast IPv6 addresses on a VLAN interface. In all cases, the prefix is 64 bits.

Applications

Stateless autoconfiguration is suitable where a link-local or global unicast IPv6 address (if a router is present) must be unique, but the actual address used is not significant. Where a specific unicast address or a unicast address from a specific range of choices is needed on an interface, DHCPv6 or static IPv6 address configuration should be used. (Refer to pages 3-8and 3-9.)

Preferred and Valid Lifetimes of Stateless Autoconfigured Addresses

The preferred and valid lifetimes of an autoconfigured global unicast address are set by the router advertisements (RA) used to generate the address, and are the autoconfiguration counterpart to the lease time assigned by DHCPv6

3-7