Avaya P332G-ML manual Static Routes, Route Redistribution

Chapter 1 Overview

Static Routes

Static routes can be configured to the P332G-ML. They are never timed-out, or lost over reboot, and can only be removed by manual configuration. Deletion (by configuration) of the IP interface deletes the static routes using this interface as well.

A static route becomes inactive if the interface over which it is defined is disabled. When the interface is enabled, the static route becomes active again.

Static routes can only be configured for remote destinations, i.e. destinations that are reachable via another router as a next hop. The next hop router must belong to one of the directly attached networks for which P332G-ML has an IP interface. “Local” static routes, such as those that have no next hop, are not allowed.

Two kinds of static routes can be configured, High Preference static routes which are preferred to routes learned from any routing protocol and Low Preference static routes which are used temporarily until the route is learned from a routing protocol. By default, a static route has Low Preference.

Static routes can be advertised by routing protocols (i.e. RIP, OSPF) as described under Route redistribution.

Static routes also support load-balancing similar to OSPF. A static route can be configured with multiple next hops so that traffic is split between these next hops.

This can be used for example to load-balance traffic between several firewalls which serve as the default gateway.

Route Redistribution

Route redistribution is the interaction of multiple routing protocols. OSPF and RIP can be operated concurrently in P332G-ML. In this case, P332G-ML can be configured to redistribute routes learned from one protocol into the domain of the other routing protocol. Similarly, static routes may be redistributed to RIP and to OSPF. Route redistribution should not be configured carelessly, as it involves metric changes and might cause routing loops in the presence of other routes with incompatible schemes for route redistribution and route preferences.

The P332G-ML scheme for metric translation in route redistribution is as follows:

•Static to RIP metric configurable (default 1)

•OSPF internal metric N to RIP metric 1

•OSPF external type 1 metric N to RIP metric 1

•OSPF external type 2 metric N to RIP metric N+1

•Static to OSPF external type 2, metric configurable (default 1)

•RIP metric N to OSPF external type 2, metric N

•Direct to OSPF external type 2, metric 1.

P332G-ML User’s Guide 11