Cisco Systems 3750E manual Configuring Static Routing for IPv6, 39-16

Chapter 39 Configuring IPv6 Unicast Routing

Configuring IPv6

To disable IPv6 CEF or distributed CEF, use the no ipv6 cef or no ipv6 cef distributed global configuration command. To reenable IPv6 CEF or dCEF if it has been disabled, use the ipv6 cef or ipv6 cef distributed global configuration command. You can verify the IPv6 state by entering the show ipv6 cef privileged EXEC command.

Configuring Static Routing for IPv6

Static routes are manually configured and define an explicit route between two networking devices. The benefits of static routes include security and resource efficiency. Static routes use less bandwidth than dynamic routing protocols because there is no requirement for routes to be calculated and communicated. The main disadvantage of using static routes is that static routes are not automatically updated, as with a dynamic routing protocol, and must be manually reconfigured if the network topology changes. Static routes are useful for smaller networks with only one path to an outside network or to provide security for a larger network for certain types of traffic.

There are types of static routes:

•Directly attached static routes—Only the output interface is specified because the destination is assumed to be directly attached to this interface. The packet destination is used as the next hop address. A directly attached static route is valid only when the specified interface is IPv6-enabled and is up.

•Recursive static routes—Only the next hop is specified, and the output interface is derived from the next hop. A recursive static route is valid only when the specified next hop results in a valid IPv6 output interface, the route does not self-recur, and the recursion depth does not exceed the maximum IPv6 forwarding recursion depth.

•Fully specified static routes—Both the output interface and the next hop are specified. The next hop is assumed to be directly attached to the specified output interface. A fully specified route is valid when the specified IPv6 interface is IPv6-enabled and up.

•Floating static routes—Any of the three types of static routes can be floating static routes, used to back up dynamic routes learned through configured routing protocols. A floating static route is configured with a less efficient administrative distance than the routing protocol it is backing up. Therefore, the dynamic route is always used for routing traffic in preference to the floating static route. If the dynamic route is lost, the floating static route is used in its place.

Note Before configuring a static IPv6 route, you must enable routing by using the ip routing global configuration command, enable the forwarding of IPv6 packets by using the ipv6 unicast-routingglobal configuration command, and enable IPv6 on at least one Layer 3 interface by configuring an IPv6 address on the interface.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
39-16	OL-9775-02