Note
If the backbone is running OSPF as well, you can enable aggregation only by configuring the 192.168.24.0 network in a different OSPF Area.
Route Rank
The route rank is the value that the routing subsystem uses to order routes from different protocols to the same destination.
You cannot use rank to control the selection of routes within a dynamic interior gateway protocol (IGP); this is accomplished automatically by the protocol and is based on the protocol metric. You can use rank to select routes from the same external gateway protocol (EGP) learned from different peers or autonomous systems.
The rank value is an arbitrarily assigned value used to determine the order of routes to the same destination in a single routing database. Each route has only one rank associated with it, even though rank can be set at many places in the configuration. The route derives its rank from the most specific route match among all configurations.
The active route is the route installed into the kernel forwarding table by the routing subsystem. In the case where the same route is contributed by more than one protocol, the one with the lowest rank becomes the active route.
Some
Rank Assignments
A default rank is assigned to each protocol. Rank values range from 0 to 255, with the lowest number indicating the most preferred route.
The table below summarizes the default rank values.
Preference of | Default |
|
|
Interface routes | 0 |
OSPF routes | 10 |
Static routes | 60 |
IGRP routes | 80 |
RIP routes | 100 |
Aggregate routes | 130 |
|
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Nokia Network Voyager for IPSO 4.0 Reference Guide | 401 |
