Ospf point-to-point links, Figure 17 – Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 User Manual

Page 187

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Brocade ICX 6650 Layer 3 Routing Configuration Guide

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OSPF overview

An Autonomous System Boundary Router (ASBR) is a router that is running multiple protocols and
serves as a gateway to routers outside an area and those operating with different protocols. The
ASBR is able to import and translate different protocol routes into OSPF through a process known
as redistribution. For more details on redistribution and configuration examples, refer to

“Enabling

route redistribution”

on page 200.

FIGURE 17

OSPF operating in a network

OSPF point-to-point links

One important OSPF process is Adjacency. Adjacency occurs when a relationship is formed
between neighboring routers for the purpose of exchanging routing information. Adjacent OSPF
neighbor routers go beyond the simple Hello packet exchange; they exchange database
information. In order to minimize the amount of information exchanged on a particular segment,
one of the first steps in creating adjacency is to assign a Designated Router (DR) and a Backup
Designated Router (BDR). The Designated Router ensures that there is a central point of contact,
thereby improving convergence time within a multi-access segment.

Area 0.0.0.0 Backbone

Area 192.168.1.0

Area 10.5.0.0

Area 192.168.0.0

Router A

Router B

Router C

Router D

Router E

Router F

Router G

10.5.1.1

Area Border
Router (ABR)

Virtual Link

Area Border

Router (ABR)

Autonomous System

Border Router (ASBR)

RIP Router

10.5.1.1

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