4A0-105: Nokia Virtual Private LAN ServicesDemo

By Nokia · Question Mode

QuestionQ149

VPLS Features

When a PE node receives a PBB-encapsulated frame on a B-VPLS, how does it identify the l-VPLS to which the frame belongs?

  • A The l-TAG in the l-SID is inspected to determine where the frame should be delivered.
  • B When the B-MAC header is stripped the customer MAC address is then looked up in the FDB
  • C The l-SID in the l-TAG is inspected to determine where the frame should be delivered.
  • D The PE inspects the service label in the MPLS header before stripping the B-MAC header.
Explanation

The I-TAG contains the I-SID, the PBB service-instance identifier used to associate the frame with its appropriate I-VPLS service. The B-component maps I-SIDs to the relevant service context; B-MAC addresses are used for backbone forwarding rather than for identifying the inner service instance.

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