Extreme Networks ExtremeWare XOS 10.1, Manual

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192 ExtremeWare XOS 10.1 Concepts Guide
Interior Gateway Protocols
Figure 33: Virtual link using Area 1 as a transit area
Virtual links are also used to repair a discontiguous backbone area. For example, in Figure 34, if the
connection between ABR1 and the backbone fails, the connection using ABR2 provides redundancy so
that the discontiguous area can continue to communicate with the backbone using the virtual link.
Figure 34: Virtual link providing redundancy
ABR ABR
EX_044
Area 2 Area 1 Area 0
Virtual link
ABR 1 ABR 2
EX_045
Area 2
Area 0
Area 1 Area 3
Virtual link