JN0-664 Exam - Question 55

Question

Click the Exhibit button.

Referring to the exhibit, the PE-to-CE protocol being used is OSPF for the L3VPN. Also, there is an OSPF neighborship between CE-1 and CE-2.

Which statement is correct in this situation?

Examice · Accepted Answer

In an OSPF network, routes are preferred based on their OSPF type. OSPF prefers intra-area routes (Type 1 and Type 2 LSAs) over inter-area routes (Type 3 LSAs), and both of these are preferred over external routes (Type 5 LSAs). In this scenario, the direct link between CE-1 and CE-2 is an intra-area link (Type 1 LSA), which is more preferred than the L3VPN routes, which would be Type 3 or Type 5 LSAs. Therefore, hosts at Site-1 will reach hosts at Site-2 through the CE-1 and CE-2 link by default.

Bob_Smith · Answer

I say C , as OSPF prefers Type 3 (network) over Type 5 (External) which would be redistributed from the BGP L3VPN.  In this case, you have to use an OSPF Sham Link between the PEs to make that link more preferred

fukJUNIPER · Answer

because the link from Site 1 to Site 2 will be a L3VPN link with the OSPF route the being LSA type 3 (since CE1 and CE2 are in the same area, otherwise it would have been an external Type 5 link).  However, the direct link from CE1 - CE2 will be LSA Type 1, and that is more preferred.

easynet13 · Answer

C is correct.

bololbno · Answer

@Bob_Smith you are right answer C. without sham link always the backdoor link will be preferred no matter how much metric you'll configure to discourage the route.

ce57f43 · Answer

C is the correct answer

yaronas · Answer

Answer C

antigel8 · Answer

C. because the route learnt through the L3VPN is going to be a type 5 while the route coming from site-2 CE is going to be a type 3. If L3VPN must be used as primary then a shame-link setup must take place.

JN0-664 Exam - Question 55

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