Which of the following do you need to take into account when designing IS-IS over NBMA hub- and-spoke topology? (Select two.)

Question

Options

• AHub-and-spoke interfaces must be configured with the same network type.
• BHub interfaces can be configured as multipoint, while spokes should be configured as point- to-
• COnly L2 must be used over the NBMA network.
• DHubs must be configured as L1/L2, whereas the spokes must be configured as L1 only.
• EHub WAN interfaces should be configured with point-to-point subinterfaces, whereas the spokes

• A
  79% (34)
• B
  5% (2)
• C
  2% (1)
• D
  14% (6)

Explanation

IS-IS over NBMA hub-and-spoke requires careful interface configuration for adjacencies to form correctly. (A) IS-IS requires that neighboring interfaces share the same network type - if one side is configured as point-to-point and the other as broadcast, the adjacency will not establish. Consistency is mandatory. (E) The recommended design is to configure hub WAN interfaces as point-to-point subinterfaces - one subinterface per spoke - with each subinterface treating the hub-to-spoke circuit as a dedicated point-to-point link. Spoke interfaces are similarly configured as point-to-point. This eliminates NBMA multipoint neighbor discovery complexity, avoids DIS election issues, and provides a clean, scalable topology. Option B describes a mixed multipoint/point-to-point configuration that would violate the matching requirement in A. Option D describes a mixed L1/L2 configuration that is not specific to NBMA design.

No community discussion yet for this question.