Brocade Communications Systems FastIron X Series User Manual

OSPFv2
• OSPF overview............................................................................................................................................................................................... 223
• OSPF point-to-point links.......................................................................................................................................................................... 225
• Designated routers in multi-access networks.....................................................................................................................................225
• Designated router election in multi-access networks......................................................................................................................225
• OSPF RFC 1583 and 2328 compliance...........................................................................................................................................227
• Reduction of equivalent AS external LSAs.......................................................................................................................................... 227
• Support for OSPF RFC 2328 Appendix E.........................................................................................................................................229
• OSPF graceful restart...................................................................................................................................................................................230
• Conguring OSPF......................................................................................................................................................................................... 232
• OSPF non-stop routing...............................................................................................................................................................................256
• Synchronization of critical OSPF elements.........................................................................................................................................256
• Standby module operations.......................................................................................................................................................................257
• Enabling and disabling NSR...................................................................................................................................................................... 258
• Disabling conguration.................................................................................................................................................................................259
• OSPF distribute list........................................................................................................................................................................................260
• Displaying OSPF information................................................................................................................................................................... 271
• Clearing OSPF information........................................................................................................................................................................289
OSPF overview
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 oods 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.
The Brocade device supports the following types of LSAs, which are described in RFC 2328 and 3101:
• 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 dened as a number of networks, all of which share the same routing and administration characteristics.
An AS can be divided into multiple areas. 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 ooding 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 ooding by dening 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.
FastIron Ethernet Switch Layer 3 Routing
53-1003627-04 223

Brocade Communications Systems FastIron X Series Specifications

General

Brand	Brocade Communications Systems
Model	FastIron X Series
Category	Switch
Language	English