Exam 350-501 topic 1 question 24 discussion

The Answer is B, but the wording of this question is bad. Serial links default to P2P OSPF network type while a ethernet will default to broadcast. Both of the peers would become fully adjacent, but would have issues after the SPF calculation.. My first instinct was different encapsulations, and internetworking wasn't configured correctly, but this is ONLY a CE question. We must assume the Provide network is setup perfectly

The correct answer is B. Why? First, In the question it clearly says that you have to assume the AToM is configured correctly. Secondly, clearly you see that the network type is not specified and the default types for ethernet is broadcast with DR whereas serial is point-to-point, these don't match.

D cannot be correct because it is stated that the configuration is on the CEs. The CEs on an L2VPN implementation will not have any xconnect configuration since they are agnostic to the transport that connects them. The OSPF adjacency between the two will not work because the default OSPF network type is different on a fastethernet and a serial interface.

You need loopback to be configure in CE, so Answer is C https://community.cisco.com/t5/service-providers-knowledge-base/configuration-example-atom-any-transport-over-mpls-for-like-to/ta-p/3144810

Sorry, my previous understanding is wrong. Here, CE routers, and it doesn't do anything with xconnect; only PE does xconnect. Hence, D is wrong. OSPF works with L2VPN, hence A is wrong. OSPF can't build neighbour adjacency if there is a network type mismatch; hence, the correct answer is B.

Agree with "sushil_bhattacharjee". Correct Answer should be "D".

For instance, it looks like [CE1<-->PE1<-->P1<-->P2<-->PE2<-->CE2] A. is not correct. Since OSPF works with L2VPN B. There is no neighbourship in between CE1 and CE2, rather it is CE1 with PE1 and CE2 with PE2. C. It is not mandatory to add loopback. So it is not correct. D. It requires to add the "xconnect" command under the interface in CE rotuers which are missing in the display. It requires to add under the interface command in the CE1 and CE2 "Router(config)# interface <interface-type>/<interface-number> Router(config-if)# xconnect <peer-address> <vc-id> encapsulation mpls". Therefore, Answer D is correct, in my opinion.

Both network types should be same

I think the correct answer is D. https://www.cisco.com/en/US/docs/ios/12_4t/mpls/configuration/guide/tpseudo.html#wp1054177