Abr area 2 area 1, Area 0 – Allied Telesis AT-8550 User Manual
Page 162
Overview of OSPF
9-8
Figure 9-1 Virtual Link for Stub Area
Virtual links are also used to repair a discontiguous backbone area.
For example, in
, 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 9-2 Virtual Link Providing Redundancy
LINK
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GIGABIT ETHERNET SWITCH
ACTIVITY
LINK
1000BASE-X NETWORK PORTS
LINK
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GIGABIT ETHERNET SWITCH
ACTIVITY
LINK
1000BASE-X NETWORK PORTS
ABR
ABR
Area 2
Area 1
Virtual link
Area 0
LINK
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GIGABIT ETHERNET SWITCH
ACTIVITY
LINK
1000BASE-X NETWORK PORTS
ABR 1
ABR 2
Area 0
Area 1
Area 2
Area 3
Virtual link
LINK
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GIGABIT ETHERNET SWITCH
ACTIVITY
LINK
1000BASE-X NETWORK PORTS