FD, RD,FS in EIGRP

What is feasible distance

Best metric along a path to a destination network, including the metric to the neighbor advertising that path

What is reported distance

Reported distance is the total metric along a path to a destination network as advertised by an upstream neighbor

What is feasible successor

A feasible successor is a path whose reported distance is less than the feasible distance (current best path)

 

How many routes are available for router One to reach Network A

Two routes

Through router 4 and through three

What are the cost to reach network a from router four and three

The route through Router Four has a cost of 46277376

The route through Router Three has a cost of 20307200

What is the reported distance from router four and three

Reported distance of 307200

Metric to get to Network A from Router Four

Metric to get to Network A from Router Three

Reported distance of 307200

Which path would be chosen by router one to reach network A

Path through router three

Path through router three is feasible distance

Does router one considered path through router four as feasible successor

Yes

Reported distance to network A through Router Four is less than the feasible distance

What happen when a link between router one and router three goes down

Router one has a feasible successor through Router Four

Uses feasible successor as new feasible distance

Network converges

We have following network

How many routes are available from router one to reach network A

Two routes

One through router four with a metric of 20307200
Another through router two with a metric of  46789376

What would be the feasible distance to reach network A from router one

Path through router four

Does path through router two qualifies as the feasible successor

Reported distance from Router Two is 46277376, which is higher than the feasible distance - so this path is not a feasible successor

How many path would be seen in the topology table of router one using show ip eigrp topology command

Only path through router four

Which command can we use to see path that are not feasible successor

show ip eigrp topology all-links

What happen if a link between router one and router four goes down

Router one has only one path to reach network a

Send queries to each of its neighbors

Send query to router two

Router two has route to network A

Router two respond to query

Router four accept the path through router two to network A