IPv6 Configuration Guide K/KA/KB.15.15

For more information on this topic, see “IPv6 Router Advertisements” (page 186).
DHCPv6-relay
When a host on a given VLAN is configured to acquire configuration settings from a DHCPv6
server, it transmits a DHCPv6 request on the VLAN. If there is no DHCPv6 server on the VLAN,
you can route the host request to a server on another VLAN by enabling a DHCPv6-relay on the
routing switch and configuring a helper address on the VLAN.
The settings in the managed-config-flag and other-config-flag RA options override an
enabled DHCPv6 option in a host on the VLAN. For more information on DHCPv6-relay, see
“DHCPv6-Relay” (page 203). For information on enabling DHCPv6 requests on a host, see “Enabling
DHCPv6” (page 15).
General Steps for Enabling IPv6 Routing
The following steps provide a guide for enabling IPv6 routing on the switches covered by this guide
1. On each VLAN configure stateless address autoconfiguration and at least one IPv6 global
unicast address:
vlan n ipv6 address autoconfig
vlan n ipv6 address prefix/prefix-length eui-64
The above commands result in a link-local address and a global unicast address having a
interface ID derived from the routing switch’s MAC address. For more on this topic, or to
manually configure link-local and global unicast addressing with a non-EUI interface ID, see
“Statically configuring a link-local unicast address” (page 18).
2. Suppress automatic (default) router advertisements (RAs) on IP routing interfaces where you
need to make configuration changes or where you do not currently want these advertisements
generated:
• To globally suppress routing advertisements on the routing switch, use this command in
the global config context:
ipv6 nd suppress-ra
• To suppress routing advertisements on individual IP routing interfaces, use this command
in the context of each IP routing interface where you want the advertisements suppressed:
ipv6 nd ra suppress
The no form of the above two suppress commands disables RA suppression. For more on
RAs, see “IPv6 Router Advertisements” (page 186).
3. Enable IPv6 routing. (This command enables RA transmission on any IP routing interface where
RAs are not specifically suppressed.)
ipv6 unicast-routing
4. For non-default RA operation, configure RAs per-IP routing interface, including suppression of
RAs on any IP routing interfaces where you do not want the routing switch to transmit RAs.
(See “IPv6 Router Advertisements” (page 186))
5. Configure one or more of the following routing features:
• IPv6 static routing, see “IPv6 Static Routing” (page 180).
• DHCPv6-Relay, see “DHCPv6-Relay” (page 203).
• OSPFv3, see “OSPFv3 Routing” (page 209).
IPv6 routing operation 175