1.1.0/24
10.1.1.0/24
2000
2500
1000
1500
Router A (E0)
Router B (E1)
The IP Routing Table
Network
Metric
(Feasible Distance)
Next Hop
(EIGRP Neighbor)
Outbound
Interface
10.1.1.0/24 2000 Ethernet 0 Router A
Successor
Feasible Successor
174 Chapter 5: Implementing EIGRP
for each router, and the results represent the feasible distances that Router C must travel to reach
network 10.1.1.0/24.
Router C chooses the least-cost feasible distance (2000) and installs it in the IP routing table as
the best route to reach 10.1.1.0/24. The route with the least-cost feasible distance that is installed
in the routing table is called the successor route.
Router C then chooses a backup route to the successor called a feasible successor route, if one
exists. For a route to become a feasible successor, a next-hop router must have an advertised
distance that is less than the feasible distance of the current successor route.
If the route through the successor becomes invalid, possibly because of a topology change, or if a
neighbor changes the metric, DUAL checks for feasible successors to the destination route. If one
is found, DUAL uses it, avoiding the need to recompute the route.
Pages:
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271