Planet Technology WGS3-404 User Manual

Page 232

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WGS3 Layer 3 Switch User’s Manual

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Option

The optional OSPF capabilities supported by the neighbor. The neighbor's

optional OSPF capabilities are also listed in its Hello packets. This enables

received Hellos to be rejected (i.e., neighbor relationships will not even start to

form) if there is a mismatch in certain crucial OSPF capabilities. The OSPF

optional capabilities currently accepted include external routing capability and

TOS capability.

You need to map the binary bits to the supported options. For example, “3”

indicates both routing capability and TOS capability.

Priority

The neighbor’s router priority. This priority is used in electing the designated

router for the area in which it exists. This value will be set to zero if this router

cannot be elected.

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.

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