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Designated routers in multi-access networks, Figure 111 – Brocade BigIron RX Series Configuration Guide User Manual

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BigIron RX Series Configuration Guide

53-1002484-04

Overview of OSPF (Open Shortest Path First)

26

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

“Enable

route redistribution”

on page 779.

FIGURE 111

OSPF operating in a network

Designated routers in multi-access networks

In a network that has multiple routers attached, OSPF elects one router to serve as the designated
router (DR) and another router on the segment to act as the backup designated router (BDR). This
arrangement minimizes the amount of repetitive information that is forwarded on the network by
forwarding all messages to the designated router and backup designated routers responsible for
forwarding the updates throughout the network.

Area 0.0.0.0 Backbone

Area 192.5.1.0

Area 200.5.0.0

Area 195.5.0.0

Router A

Router B

Router C

Router D

Router E

Router F

Router G

208.5.1.1

Area Border
Router (ABR)

Virtual Link

Area Border

Router (ABR)

Autonomous System

Border Router (ASBR)

RIP Router

206.5.1.1

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