Exam JN0-663 topic 1 question 16 discussion

OSPF interface type point to point (p2p) no designated router/backup designated router election occurs Used between adjacencies involving exactly two neighbors saves time getting the adjacency to a full state Useful on back to back ethernet links

By default, a single interface can belong to only one OSPF area. You can configure a single interface to belong in multiple OSPF areas. Doing so allows the corresponding link to be considered an intra-area link in multiple areas and to be preferred over other higher-cost intra-area paths. When configuring a secondary interface, consider the following: For OSPFv2, you cannot configure point-to-multipoint and nonbroadcast multiaccess (NBMA) network interfaces as a secondary interface because secondary interfaces are treated as a point-to-point unnumbered link. Secondary interfaces are supported for LAN interfaces (the primary interface can be a LAN interface, but any secondary interfaces are treated as point-to-point unnumbered links over the LAN). In this scenario, you must ensure that there are only two routing devices on the LAN or that there are only two routing devices on the LAN that have secondary interfaces configured for a specific OSPF area. https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/topic-map/configuring-ospf-areas.html#id-example-configuring-multiarea-adjacency-for-ospf

C is correct because of secondary keyword, which will be DR plus P2p

I've tested in a lab. Also see TT98's and Sheet's answers.

C is correct answer

C: A logical interface can be configured as primary interface only for one area. For any other area for which you configure the interface, you must configure it as a secondary interface. https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/secondary-edit-protocols-ospf.html

Correct C

Agree with Sheet. adding secondary to the configuration makes the interface PtToPt Correct C

C is correct. Secondary adjacencies are always point-to-point.

It look like there should be 2 answers - C,D

D wouldn't even commit, I guess

Answer is C. This is an example of a multiarea adjacency. Interface ge-0/0/0.0 has both DR and PTP, which with ordinary OSPF adjacency rules will be impossible.