3Com 4007, Руководство по внедрению, Страница: 481 / 684

Neighbors 481
Neighbor Information Your system can display a list of all neighbors for all OSPF interfaces
defined on the system. The list includes the following information:
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Index — The Index number that corresponds to the OSPF router
interface for which neighbors have been discovered.
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Neighbor Address — The IP address of the neighboring router.
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Router ID — The router ID of the neighboring router.
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State — The state of the adjacency. You can also think of this as the
state of the conversation that is held with the neighboring router.
Possible neighbor state values:
■
Down — The initial state of a neighbor conversation. It indicates
that no recent information has been received from this neighbor.
■
Attempt — Only used on nonbroadcast networks. This value
indicates that no recent information has been received from this
neighbor, but the router tries to contact the neighbor by sending
Hello packets.
■
Init — A Hello packet has recently been seen by a neighbor, but
two-way communication has not been established.
■
Two-way — Bidirectional communication has been established.
Two-way is the most advanced state of a neighbor relationship
before beginning to establish an adjacency. In fact, the designated
router and backup designated router are selected from the set of
neighbors that are in a state of two-way communication or greater.
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Exstart — The initial step in creating an adjacency between two
routers. Adjacencies involve a master/slave relationship between
two routers, which is when that relationship is determined. The
master sends the first information describing its link state database
in the form of database description packets. The slave can only
respond to the database description packets.
■
Exchange — The router is describing its link state database by
sending database description packets to the neighbor. All
adjacencies in the exchange state are used by the flooding
procedure. Adjacencies in this state are capable of transmitting and
receiving all types of OSPF protocol packets.