The dead interval is the time in seconds that a router waits to hear from a neighbor before
declaring the neighboring router out of service. By default, the dead interval is four times the
hello interval. These timers must be the same on neighboring routers; otherwise, an adjacency
will not be established.
?– Neighbors: The Neighbors ?¬?eld lists the adjacent routers with established bidirectional
communication. This bidirectional communication is indicated when the router recognizes
itself listed in the Neighbors ?¬?eld of the hello packet from the neighbor.
afadjfjorqpoeru
39547439070713
D E
C A B
Hello
Hello
Router ID
Hello and Dead Intervals*
Neighbors
Area ID*
Router Priority
DR IP Address
BDR IP Address
Authentication Pasword*
Stub Area Flag*
*Entry must match on neighboring routers.
Introducing OSPF 143
?– Area ID: To communicate, two routers must share a common segment, and their interfaces
must belong to the same OSPF area on that segment. The neighbors must also share the same
subnet and mask. All these routers will have the same link-state information.
?– Router priority: The router priority is an 8-bit number that indicates the priority of a router.
Pages:
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229