Refer to the exhibit.
Router A is unable to reach Router B. Both routers are running IOS version 12.0. After reviewing the command output and graphic, what is the most likely cause of the problem?
A.
incorrect bandwidth configuration
B.
incorrect LMI configuration
C.
incorrect map statement
D.
incorrect IP address
Explanation:
The local DLCI from Routerl to Frame-relay cloud is 50, the local DLCI from the second router to FR cloud is 75. FR mapping from routerl to the second router is as follows: frame-relay map ip 192.168.2.1 75 broadcast
which one is router A and which is router B? If the left router has local DLCI 50 and the right is 75, isn’t the frame mapping correct?
The phrase “command output” in the question may be the key to the solution.
I looked at the two labs (one for multipoint the other for point to point) I created before.
I issued “show frame-relay map” command on both scenarios and observed the following output.
MULTIPOINT, IP’s are on the same subnet.
R1#show frame-relay map
Serial0/0 (up): ip 192.168.5.2 dlci 503(0x1F7,0x7C70), static, broadcast, CISCO, status defined, active
POINT TO POINT, IP’s are on different subnet.
R1#show frame-relay map
Serial0/0.503 (up): point-to-point dlci, dlci 503(0x1F7,0x7C70), broadcast status defined, active
Comparing these two outputs are telling me that if I see a DLCI number and and IP address in the output, then we have multipoint configuration.
Maybe this is why we can say that the ip’s are on the same subnet (even though there is no information in the question regarding what the subnet mask is).
Now, the output in the question is telling me that if you want to get to remote IP 192.168.2.1, use local DLCI 50, so this output show the result of “show frame-relay map” issued on Router A, and it indicates Multipoint configuration.
If router A (192.168.1.1) pings router B (192.168.2.1), router B gets the ICMP echo message, this direction works.
But then, router B needs to send echo-reply back to A. If there is a mapping problem on router B (if they did not map remote ip 192.168.1.1 to local DLCI 75) then Icmp-echo would not be able to get back to router A. Then router A would say he can’t reach router B. (Again, router A would not be able to know if he made it to Router B, unless he gets a reply from router B).
So, there must be a mapping configuration issue on router B. Therefore, I would choose “C. Incorrect map statement” as the answer.
With this topology and the DLCI, we can only think of “incorrect map statement”. From the topology we can deduce traffic with a DLCI of 75 will be sent to 192.168.2.1 but the text below wrongly shows “DLCI 50” for the next router 192.168.2.1 -> C is correct.