Introduction : For IPv6 Global Unicast address auto config of the clients, Router Advertisements have to be sent out with the Network prefix. For this RA needs to be enabled on the corresponding VLAN interface and Network Prefix has to be specified.
Feature Notes : Router Advertisement will help a client in a Link to identify its routers in the subnet. Also it provides information for client auto address configuration.
Environment : Can be used in any environment where Controller is acting as a Router in an IPv6 network.
Network Topology : Controller(L3 - IPv6 Router for clients) ======= Switches(L2)=======APs )))))) IPv6 clients
Configuration Steps : Below is the configuration to enable IPv6 and configure RA network prefix.
(Abilash-Lab-Cont-master-6.4) (config) #ipv6 enable
(Abilash-Lab-Cont-master-6.4) (config) #interface vlan 164
(Abilash-Lab-Cont-master-6.4) (config-subif)#ipv6 address 2001::1/64
(Abilash-Lab-Cont-master-6.4) (config-subif)#ipv6 nd ra enable
(Abilash-Lab-Cont-master-6.4) (config-subif)#ipv6 nd ra prefix 2001::/64
(Abilash-Lab-Cont-master-6.4) (config-subif)#exit
(Abilash-Lab-Cont-master-6.4) (config) #exit
(Abilash-Lab-Cont-master-6.4) #write mem
Answer : The configuration can be checked through the below commands:
(Abilash-Lab-Cont-master-6.4) #show ipv6 interface brief
Interface [Status/Protocol]
vlan 164 [ up/up ]
fe80::1a:1e00:a400:1160/64
2001::1/64
fc00:0:0:1::1/64
vlan 1 [ up/up ]
unassigned
vlan 4 [ up/down]
fe80::1a:1e00:400:1160/64
2002::2/64
loopback [ up/up ]
fe80::1a:1e0f:ff00:1160/64
(Abilash-Lab-Cont-master-6.4) #show ipv6 ra ?
status Status of IPv6 Router Advertisements
(Abilash-Lab-Cont-master-6.4) #show ipv6 ra status
IPv6 RA Status
--------------
VlanId State Prefix(es)
------ ----- ----------
164 enabled 2001::/64
(Abilash-Lab-Cont-master-6.4) #
Verification : Further verification can be packet capture can be done to validate if the Router advertisement.
Troubleshooting :
In the packet capture look for RA. In RA, in the ICMPv6 Payload it should be seen that "Prefix" field should have the network prefix configured.