H12-821_V1.0 · Question #753
IS-IS cannot run on point-to-multipoint links P2MP (Point to MultiPoint)
The correct answer is A. TRUE. IS-IS only recognizes two network types: point-to-point and broadcast (multi-access). Unlike OSPF - which defines five network types including point-to-multipoint - IS-IS has no native P2MP mode in its protocol specification, making option A correct. Without a P2MP type, IS-IS…
Question
Options
- ATRUE
- BFALSE
How the community answered
(34 responses)- A79% (27)
- B21% (7)
Explanation
IS-IS only recognizes two network types: point-to-point and broadcast (multi-access). Unlike OSPF - which defines five network types including point-to-multipoint - IS-IS has no native P2MP mode in its protocol specification, making option A correct. Without a P2MP type, IS-IS cannot model a hub-and-spoke topology where spokes cannot communicate directly; it would have to misrepresent the topology as either broadcast (causing adjacency/reachability problems) or force a workaround at the physical layer. Option B is wrong because vendor-specific hacks aside, the base IS-IS standard (ISO 10589 / RFC 5308) simply does not include P2MP as a supported link type.
Memory tip: Think "IS-IS = 2 types, OSPF = 5 types." If P2MP is in the question, OSPF handles it natively - IS-IS does not.
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