Configuration Guide User guide

1226 FastIron Configuration Guide
53-1002494-01
OSPF overview
This chapter describes how to configure OSPF Version 2 on Brocade Layer 3 Switches using the CLI.
OSPF Version 2 is supported on devices running IPv4.
NOTE
The terms Layer 3 Switch and router are used interchangeably in this chapter and mean the same
thing.
OSPF overview
Open Shortest Path First (OSPF) is a link-state routing protocol. The protocol uses link-state
advertisements (LSAs) to update neighboring routers regarding its interfaces and information on
those interfaces. The router floods these LSAs to all neighboring routers to update them regarding
the interfaces. Each router maintains an identical database that describes its area topology to
help a router determine the shortest path between it and any neighboring router.
Brocade Layer 3 Switches support the following types of LSAs, which are described in RFC 1583:
Router link
Network link
Summary link
Autonomous system (AS) summary link
AS external link
Not-So-Stubby Area (NSSA) external link
Grace LSAs
OSPF is built upon a hierarchy of network components. The highest level of the hierarchy is the
Autonomous System (AS). An autonomous system is defined as a number of networks, all of which
share the same routing and administration characteristics.
An AS can be divided into multiple areas as shown in Figure 158 on page 1227. Each area
represents a collection of contiguous networks and hosts. Areas limit the area to which link-state
advertisements are broadcast, thereby limiting the amount of flooding that occurs within the
network. An area is represented in OSPF by either an IP address or a number.
You can further limit the broadcast area of flooding by defining an area range. The area range
allows you to assign an aggregate value to a range of IP addresses. This aggregate value becomes
the address that is advertised instead all of the individual addresses it represents being
advertised. You can assign up to 32 ranges in an OSPF area.
OSPF traps Yes Yes Yes Yes Yes
Exit overflow interval Yes Yes Yes Yes Yes
Syslog messages Yes Yes Yes Yes Yes
Clearing OSPF information Yes Yes Yes Yes Yes
TABLE 212 Supported OSPF V2 features (Continued)
Feature FESX
FSX 800
FSX 1600
FWS FCX ICX 6610 ICX 6450