Foundry Networks Switch and Router Installation And Configuration Manual page 230

Foundry Switch and Router Installation and Configuration Guide
NOTE: An intra-domain protocol is a protocol that is used by routers under common administrative control. The
term "domain", used in this context, is synonymous with "autonomous system". In contrast, Border Gateway
Protocol (BGP) is an example of an inter-domain protocol. BGP is used by routers in one domain to exchange
information with routers in other domains.
RIP
RIP is a distance-vector protocol. It uses a cost value associated with each route to express the preferability of
that route. Generally, the cost is equivalent to the number of hops in the route, but Foundry devices allow you to
bias the preferability of a route by changing its cost. You also can configure the router to prefer one route over
another equal cost route.
By default, Foundry routers using RIP propagate route information to other RIP routers by sending route updates
every 30 seconds. You can change this update interval if needed.
You can enable Foundry routers to use RIP version 1, RIP version 1 with version 2 compatibility, or RIP version 2
to manage IP routes. The default is version 2.
As described in "Static IP Routes, Address Resolution Protocol (ARP) Entries, and Reverse ARP (RARP) Entries"
on page 8-21, you also can make static route entries if needed.
See "Configuring IP" on page 15-1 for information.
Open Shortest Path First (OSPF) Routing
OSPF is a link-state routing protocol. Each router that runs OSPF uses information from its own interfaces and
from other OSPF routers to build a topological map of the network. OSPF routers exchange link-state databases
and then periodically send link-state advertisements to notify other routers of route changes.
Foundry routers are configured to be compliant with RFC 1583 OSPF V2 (RFC 1583) by default. You also can
configure Foundry routers to run the latest OPSF standard, RFC 2178.
See "Configuring OSPF" on page 17-1 for information.
Border Gateway Protocol (BGP4) Routing
BGP4 allows you to configure Foundry Layer 3 Switches to route traffic between Autonomous Systems (ASs) and
to maintain loop-free routing. BGP allows the routers within the AS to communicate even when those routers are
running different Interior Gateway Protocols (IGPs) such as RIP and OSPF.
The Foundry implementation of BGP4 is based on RFCs 1771, 1745 (OSPF Interactions), 1997 (BGP
Communities Attributes), and 1965 (Confederations).
See "Configuring BGP4" on page 19-1 for information.
IP Access and QoS Filters
You can control the IP traffic that the Foundry router receives and forwards by defining IP access policies. An IP
access policy can filter on source IP address, destination IP address, UDP port number, or TCP port number. For
example, if you want to permit Telnet access only to specific IP addresses, you can create permit policies for
those IP addresses.
You also can use IP access policies to specify the Quality of Service (QoS) packets that certain Layer 4 session
should receive. A Layer 4 session is a combination of the source and destination addresses and the TCP or UDP
port number. For more information about QoS, see "IronClad Quality of Service (QoS)" on page 11-1.
You assign policies to individual ports by defining access policy groups. An access policy group identifies a list of
policies and a set of ports to which the policies are applied. Access policies are applied in the order you list them
in the access policy group.
8 - 22 December 2000