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Cisco Catalyst Switch Module 3110 and 3012 for IBM BladeCenter Software Configuration Guide
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Chapter 39 Configuring IPv6 Host Functions and Unicast Routing
Configuring IPv6
Configuring Static Routes 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 routes are not calculated and communicated. The main disadvantage
of using static routes is that they 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 backs 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.
Note Before configuring a static IPv6 route on a Catalyst Switch Module 3110, you must enable routing by
using the ip routing global configuration command, enable the forwarding of IPv6 packets by using the
ipv6 unicast-routing global configuration command, and enable IPv6 on at least one Layer 3 interface
by configuring an IPv6 address on the interface.
