User`s guide

76 XSR User’s Guide
IP Routing Protocols Chapter 5
Configuring IP
IP Routing Protocols
Routing is one of the most important functions of IP. Routing information,
which is stored in a routing table, is used by the XSR to determine the route
for each of the packets that pass through it. The following routing features are
supported on the XSR:
 RIP
 OSPF
 Static routes
 Default network
 CIDR (IP classless)
When you run multiple routing protocols, the XSR assigns a weight to each of
them. For more information, refer to “Routing Priorities” on page 82.
RIPv1 and v2
The Routing Information Protocol (RIP) is a distance-vector protocol based on the
Bellman-Ford algorithm to learn the shortest path between two points in a
network. RIP is used only on networks whose longest path is 15 hops or less and
is marked by the following limits on the XSR:
 MD5 authentication not supported
 Static redistribution permitted only
 Total number of static routes, routes, interfaces, and RIP networks
limited depending on the size of installed memory
 Distribution lists require an ACL to be configured
RIP uses request and response messages. Requests ask for all or part of the
routing table entries and responses can be sent for one of the following reasons:
 Response to a specific query
 Regular updates (unsolicited response)
 Triggered updates caused by a route change
RIP specifications are RFC-1058 for RIPv1 and RFC-2453 for RIPv2. It is
supported on the XSR with the following features:
 Set globally with the
router rip and per interface with the network
commands: they support RIP on both LAN and WAN interfaces with
these default values: Receive RIPv1 and v2, Transmit RIPv1, no
redistribution, no filtering and Split Horizon with no poison.