6rd Configuration Example
6rd is a IPv6 transitioning mechanism to allow for stateless tunneling of IPv6 over IPv4. It is intended as a mechanism to tunnel across an ISP's IPv4 only access network.
This example shows the configuration of a 6rd Border Relay (BR) and the configuration of the corresponding 6rd Customer Edge (CE) router. 6rd is specified in RFC5969.
ipv6 general-prefix DELEGATED_PREFIX 6rd Tunnel0 interface Loopback0 ip address 10.0.0.1 255.255.255.0 ! interface Tunnel0 tunnel source Loopback0 tunnel mode ipv6ip 6rd tunnel 6rd ipv4 prefix-len 8 tunnel 6rd prefix 2001:db80::/28 ipv6 address DELEGATED_PREFIX::/128 anycast ! ipv6 route 2001:db80::/28 Tunnel0 ipv6 route 2001:db80:0:100::/52 Null0
ipv6 general-prefix DELEGATED_PREFIX 6rd Tunnel0 interface Dialer0 ip address dhcp ! (10.0.0.10) ! interface Tunnel0 tunnel source Dialer0 tunnel mode ipv6ip 6rd tunnel 6rd ipv4 prefix-len 8 tunnel 6rd prefix 2001:db80::/28 tunnel 6rd br 10.0.0.1 ipv6 address DELEGATED_PREFIX ::/128 anycast ! interface Ethernet0 ipv6 address DELEGATED_PREFIX ::/64 eui-64 ! ipv6 route 2001:db80::/28 Tunnel0 ipv6 route ::/0 Tunnel0 2001:db80:0000:1000:: ipv6 route 2001:db80:0000:A000::/52 Null0
Note there is a caveat in IOS today where it would reject overlapping IPv6 addresses as configured above, ie., a /128 on the tunnel and /64 on the LAN interface, with the %IPV6_ADDRESS-3-ADDRESS_CFG error. The workaround is to remove the IPv6 address configuration from the Tunnel interface and use the command ipv6 enable to have a link-local ipv6 address assigned to the Tunnel.
Related show Commands
This section provides information you can use to confirm your configuration is working properly.
Certain show commands are supported by the Output Interpreter Tool (registered customers only), which allows you to view an analysis of show command output.
show tunnel 6rd
Software releases and platforms
IOS 15.1(3)T for 800, 1800, 1900, 2800, 2900, 3800, 3900 Series IOS-XE 3.1S for ASR 1K