Alcatel Carrier Internetworking Solutions 060187-10 REV D 사용자 설명서

OSPF Overview

Configuring OSPF

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OmniSwitch 6600 Family Advanced Routing Configuration Guide

It is possible to define areas in such a way that the backbone is no longer contiguous. (This is not an ideal 
OSPF configuration, and maximum effort should be made to avoid this situation.) In this case the system 
administrator must restore backbone connectivity by configuring virtual links.

Virtual links can be configured between any two backbone routers that have a connection to a common 
non-backbone area. The protocol treats two routers joined by a virtual link as if they were connected by an 
unnumbered point-to-point network. The routing protocol traffic that flows along the virtual link uses 
intra-area routing only, and the physical connection between the two routers is not managed by the 
network administrator (i.e., there is no dedicated connection between the routers as there is with the OSPF 
backbone).

In the above diagram, Router A and Router B are connected via a virtual link in Area 1, which is known as 
a transit area. See 

 for more information.