Switch User Manual

138 IP Routing Configuration and Management
OSPF network example
To create the configuration illustrated above for router R1, use the following
commands:
5530-24TFD(config)# vlan create 2 type port
5530-24TFD(config)# vlan mem add 2 1
5530-24TFD(config)# interface vlan 2
5530-24TFD(config-if)# ip address 172.3.1.1 255.255.255.0
5530-24TFD(config-if)# ip ospf network passive
The Nortel Ethernet Routing Switch 5500 Series supports the following
types of networks:
•
Broadcast - Automatically discovers every OSPF router on the network
by sending OSPF hellos to the multicast group AllSPFRouters
(224.0.0.5). Neighboring is automatic and requires no configuration.
This interface type is typically used in an Ethernet environment.
•
Passive - Allows interface network to be included in OSPF without
generating LSAs or forming adjacencies. Typically used on an access
network, or on an interface that is used for BGP peering. This also
limits the amount of CPU cycles required to process the OSPF routing
algorithm.
Configuring OSPF areas
In large networks with many routers and networks, the link state database
(LSDB) and routing table can become very large. Large route tables and
link state databases (LSDB) consume memory. The processing of link state
advertisements results in more CPU cycles required to make forwarding
decisions. To help reduce these undesired effects, an OSPF network can
be divided into subdomains called areas. An area is made up of a number
of OSPF routers that have the same area identification.
By dividing a network into multiple areas, a separate LSDB, consisting of
router link state advertisements (LSA) and network LSAs are maintained
for each area. Each router within an area maintains an LSDB only for the
area to which it belongs. For example, the area router LSAs and network
LSAs are not flooded beyond the area borders.
Nortel Ethernet Routing Switch 5500 Series
Configuration-IP Routing Protocols
NN47200-503 03.01 Standard
5.1 27 August 2007
Copyright © 2005-2007, Nortel Networks
.