4A0-112: Nokia IS-IS Routing ProtocolDemo

By Nokia · Question Mode

QuestionQ8

SR OS Control Plane Security

Several differences exist between IS-IS Hello packets used on broadcast interfaces and those used on point-to-point interfaces.

Which of the following statements is FALSE?

  • A On broadcast interfaces there are different Hello packet types for level-1 and level-2 adjacencies, whereas on point-to-point interfaces there is a single Hello packet type.
  • B The multicast MAC addresses to which the Hello messages are sent are different on broadcast interfaces and on point-to-point interfaces.
  • C The neighbors are identified using their interface MAC addresses on broadcast Hello messages and using their system IDs on point-to-point Hello messages.
  • D Broadcast Hello messages identify the elected designed IS (DIS) and point-to-point Hello messages do not.
Explanation

IS-IS identifies an intermediate system by its System ID on both LAN and point-to-point circuits. A LAN Hello is transported with a source MAC address and can record that link-layer address for the LAN attachment, but the MAC address does not replace the System ID as the IS-IS neighbor identity. IS-IS defines distinct Level-1 and Level-2 LAN Hello formats, a single point-to-point Hello format, and LAN Hellos carry the LAN ID associated with the DIS.

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