Cisco ENCOR (MPLS) 2

Question 1

Which MPLS label operation replaces an existing label with a new label?

Accepted Answer

Swap

Answer

The Swap operation replaces the top label in the MPLS stack with a new label at each transit LSR.

Question 2

What is the default MPLS label value reserved for the IPv4 explicit null label?

Accepted Answer

0

Answer

Label value 0 is the IPv4 Explicit Null label, signaling the egress PE to pop the label and forward based on the IPv4 header.

Question 3

In an MPLS network, what does the term 'LSP' stand for?

Accepted Answer

Label Switched Path

Answer

LSP stands for Label Switched Path, which is the unidirectional path from ingress to egress LSR that packets follow.

Question 4

Which protocol can be used to signal MPLS LSPs and also carries QoS traffic engineering constraints?

Accepted Answer

RSVP-TE

Answer

RSVP-TE (Resource Reservation Protocol - Traffic Engineering) signals LSPs and carries bandwidth and constraint information for TE tunnels.

Question 5

What is the role of a P (Provider) router in an MPLS VPN architecture?

Accepted Answer

Performs label swap operations in the core

Answer

P routers are core MPLS routers that only perform label swap operations and have no knowledge of VPN or customer routes.

Cisco ENCOR Practice Test