Refer to the exhibit. BigBids Incorporated is a worldwide auction provider. The network uses
EIGRP as its routing protocol throughout the corporation. The network administrator does
not understand the convergence of EIGRP.
Using the output of the show ip eigrp topology all-linkscommand, answer the
administrator’s questions.
Core#1show ip eigrp topology all-links
IP EIGRP Topology table for AS(65001)/ID(172.17.10.1)
Codes: P – Passive, A – Active, U – Update, Q – Query, R -Reply, r – reply Status, s – sia Status
P 172.17.3.128/25, 2 successors, FD is 30720, semo 9
via 172.17.10.2 (30720/28160), FastEthernet0/1
via 172.17.3.2 (30720/28160), FastEthernet0/3
P 10.140.0.0/21, 1 successors, FD is 156160, semo 16
via 172.17.3.2 (156160/128256), FastEthernet0/3
via 172.17.10.2 (157720/155160), FastEthernet0/1
P 172.17.10.0/24, 1 successors, FD is 28160, semo 1
via Connected, FastEthernet0/1
P 172.17.0.0/30, 1 successors, FD is 20514560, semo15
via 172.17.1.1 (20514560/205122000), FastEthernet0/2
via 172.17.10.2 (20516120/20513560), FastEthernet0/1
P 172.17.1.0/24, 1 successors, FD is 28160, semo 2
via Connected, FastEthernet0/2
P 172.17.2.0/24, 1 successors, FD is 30720, semo 8
via 172.17.10.2 (30720/28160), FastEthernet0/1
via 172.17.3.2 (33280/30720), FastEthernet0/3
P 172.17.3.0/25, 1 successors, FD is 28160, semo 3
via Connected, FastEthernet0/3
Which two networks does the Core1 device have feasible successors for? (Choose two)
Select the 2 best responses.
A.
172.17.0.0/30
B.
172.17.1.0/24
C.
172.17.2.0/24
D.
172.17.3.0/25
E.
172.17.3.128/25
F.
10.140.0.0/24
Explanation:
To understand the output of the “show ip eigrp topology all-links command” command, let’s
analyze an entry (we choose the second entry because it is better for demonstration than
the first one)
The first line tells us there is only 1 successorfor the path to 10.140.0.0/24 network but
there are 2 lines below. So we can deduce that one line is used for successor and the other
is used for another route to that network. Each of these two lines has 2 parameters: the first
one (“156160″or “157720″) is the Feasible Distance (FD) and the second (“128256″or
“155160″) is the Advertised Distance (AD) of that route.
The next thing we want to know is: if the route via172.17.10.2 (the last line) would become
the feasible successor for the 10.140.0.0/24 network. To figure out, we have to compare the
Advertised Distance of that route with the FeasibleDistance of the successor’s route, if AD
< FD then it will become the feasible successor. Inthis case, because AD (155160) < FD
(156160) so it will become the feasible successor.
Therefore we can conclude the network 10.140.0.0/24has 1 feasible successor.
After understanding the output, let’s have a look at the entire output:
Because the question asks about feasible successor so we just need to focus on entries
which have more paths than the number of successor.In this case, we find 3 entries that
are in blue boxes because they have only 1 successor but has 2 paths, so the last path can
be the feasible successor.
By comparing the value of AD (of that route) with the FD (of successor’s route) we figure out
there are 2 entries will have the feasible successor: the first and the second entry. The third
entry has AD = FD (30720) so we eliminate it.