4A0-C03: Nokia NRS II Composite Exam: IS-IS versionDemo

By Nokia · Question Mode

QuestionQ16

Multiprotocol Label Switching

A Nokia 7750 SR label-switches a packet that it receives. The packet has an outer-label TTL of 250 and an inner-label TTL of 251. Which of the following statements is TRUE?

  • A The outer label TTL will be 249 and the inner label TTL will be 250.
  • B The outer label TTL will be 249 and the inner label TTL will be 251.
  • C The outer label TTL will be 251 and the inner label TTL will be 251.
  • D The outer label TTL will be 251 and the inner label TTL will be 252.
Explanation

An MPLS label-switching router decrements the TTL of the top label as it swaps that label for forwarding. The inner label remains unprocessed and retains its existing TTL, resulting in an outer-label TTL of 249 and an inner-label TTL of 251.

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