Configuration Guide Manual

Brocade TurboIron 24X Series Configuration Guide 605
53-1003053-01
Chapter
23
Configuring OSPF Version 2 (IPv4)
In this chapter
•Overview of OSPF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
•Configuring OSPF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
•Clearing OSPF information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644
•Displaying OSPF information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
This chapter describes how to configure OSPF Version 2 on 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.
Overview of OSPF
OSPF is a link-state routing protocol. The protocol uses link-state advertisements (LSA) 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.
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
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 94 on page 606. 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.