Exam JN0-363 topic 1 question 52 discussion

A and B. Explanation: Segment Routing Adjacencies (Option A): Segment routing adjacencies are locally significant and lightweight. They do not require complex protocols or extensive state management, which makes them efficient in terms of resource usage. Label Advertisement Through OSPF Updates (Option B): Segment routing labels, known as Segment Identifiers (SIDs), can be advertised using IGP protocols such as OSPF or IS-IS. These labels are distributed as part of the routing protocol updates. Incorrect Options: C. There are no segment routing adjacencies to maintain: This is false because segment routing adjacencies do exist, but they require minimal resources to maintain. D. Label assignments can be advertised through LDP updates: This is incorrect because segment routing does not rely on the Label Distribution Protocol (LDP). Instead, it uses IGP protocols like OSPF or IS-IS for label distribution.

It's AB. Segment routing requires fewer resources than other protocols, this is one of the benefits. Juniper's own documentation states that labels can be readvertised in OSPF - this is not unique to Juniper. It can't be C because segment routing has adjacencies - hence the term "segments."

To start with, segment routing is not a protocol in the same way that LDP or RSVP are protocols. There are no segment routing hello messages, no segment routing sessions or adjacencies, and no explicitly signaled segment routing LSPs. Instead, segment routing piggybacks off of IS-IS or OSPF, and advertises label information directly in these protocols.