State

The communication state for two adjacent routers:

 

 

 

 

 

Down:

This is the initial state of a neighbor conversation. It

 

 

 

 

indicates that there has been no recent information

 

 

 

 

received from the neighbor.

 

 

 

Attempt:

This state is only valid for neighbors attached to

 

 

 

 

non-broadcast networks. It indicates that no recent

 

 

 

 

information has been received from the neighbor, but that

 

 

 

 

the router is attempting to contact the neighbor by sending

 

 

 

 

Hello packets.

 

 

 

Init:

A Hello packet has recently been seen from the neighbor.

 

 

 

 

However, bidirectional communication has not yet been

 

 

 

 

established with the neighbor.

 

 

 

2-Way:

Communication between the two routers has been

 

 

 

 

established. This is the most advanced state short of

 

 

 

 

beginning adjacency establishment. Note that both the

 

 

 

 

Designated Router and Backup Designated Router are

 

 

 

 

selected from the set of neighbors in state 2-Way or

 

 

 

 

greater.

 

 

 

ExStart:

This is the first step in creating an adjacency between the

 

 

 

 

two neighboring routers. The goal of this step is to decide

 

 

 

 

which router is the master, and to decide upon the initial

 

 

 

 

sequence number. Neighbor conversations in this state or

 

 

 

 

greater are called adjacencies.

 

 

 

Exchange:

The router is describing its entire link state database by

 

 

 

 

sending database description packets to the neighbor.

 

 

 

 

(Each database description packet has a sequence

 

 

 

 

number, and is explicitly acknowledged.) All adjacencies in

 

 

 

 

Exchange state or greater are used by the flooding

 

 

 

 

procedure. In fact, these adjacencies are fully capable of

 

 

 

 

transmitting and receiving all types of OSPF routing

 

 

 

 

protocol packets.

 

 

 

Loading:

Link State Request packets are sent to the neighbor

 

 

 

 

asking for more recent advertisements that have been

 

 

 

 

discovered (but not yet received) in the Exchange state.

 

 

 

Full:

The neighboring routers are fully adjacent. These

 

 

 

 

adjacencies will now appear in router links and network

 

 

 

 

links advertisements.

 

 

Events

The number of events encountered that cause a neighbor state

 

 

 

change since boot up.

 

3.8.Resetting the System

Use the Restart command under the Main Menu to reset the management agent. The reset screen is shown below.

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