| State | The communication state for two adjacent routers: |
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| Down: | This is the initial state of a neighbor conversation. It Indicates |
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| that there has been no recent information received from the |
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| neighbor. |
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| Attempt: | This state is only valid for neighbors attached to |
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| Information has been received from the neighbor, but that the |
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| router is attempting to contact the neighbor by sending Hello |
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| packets. |
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| Init: | A Hello packet has recently been seen from the neighbor. |
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| However, bidirectional communication has not yet been |
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| established with the neighbor. |
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| Communication between the two routers has been |
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| established. This is the most advanced state short of |
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| beginning adjacency establishment. Note that both the |
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| Designated Router and Backup Designated Router are |
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| selected from the set of neighbors in state |
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| ExStart: | This is the first step in creating an adjacency between the two |
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| neighboring routers. The goal of this step is to decide which |
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| router is the master, and to decide upon the initial sequence |
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| number. Neighbor conversations in this state or greater are |
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| called adjacencies. |
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| Exchange: | The router is describing its entire link state database by |
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| sending database description packets to the neighbor. (Each |
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| database description packet has a sequence number, and is |
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| explicitly acknowledged.) All adjacencies in Exchange state or |
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| greater are used by the flooding procedure. In fact, these |
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| adjacencies are fully capable of transmitting and receiving all |
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| types of OSPF routing protocol packets. |
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| Loading: | Link State Request packets are sent to the neighbor asking |
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| for more recent advertisements that have been discovered |
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| (but not yet received) in the exchange state. |
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| Full: | The neighboring routers are fully adjacent. These adjacencies |
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| will now appear in router links and network links |
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| advertisements. |
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| Events | The number of events encountered that cause a neighbor state change |
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| since boot up. |
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Note:
To scroll through the table, use the <Next Page> and <Prev Page> buttons. To display a specific page, set the page number in the Page field and select <Apply>.
Displaying the Virtual Neighbor Table
Virtual links can be used to link an area isolated from the backbone, to create a redundant link between any area and the backbone to help prevent partitioning, or to connect two existing backbone areas into a common backbone. Note that the processes of establishing a active link between virtual neighbors is similar to that used for
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