Cisco ENCOR (MPLS) 4

Question 1

Which MPLS feature allows a single physical interface to carry traffic for multiple VPNs without sub-interfaces?

Accepted Answer

VRF-Lite

Answer

VRF-Lite associates a physical or logical interface directly to a VRF, allowing multiple VPN instances on one router without MPLS label switching in the core.

Question 2

In MPLS Segment Routing (SR-MPLS), what does a Node Segment ID (SID) represent?

Accepted Answer

A globally unique MPLS label identifying a specific router

Answer

A Node SID is a globally significant MPLS label (from the SRGB) that uniquely identifies a node in the SR domain and instructs transit routers to forward toward that node.

Question 3

What is the Segment Routing Global Block (SRGB)?

Accepted Answer

A reserved range of MPLS labels used for Segment Routing SIDs

Answer

The SRGB is the range of MPLS label values reserved on a router for Segment Routing, from which Node and Prefix SIDs are allocated.

Question 4

In MPLS TE Fast Reroute (FRR), what is a 'backup tunnel'?

Accepted Answer

A pre-signaled LSP used to reroute traffic around a failure

Answer

FRR backup tunnels are pre-established RSVP-TE LSPs that provide sub-50ms rerouting around a protected link or node failure.

Question 5

Which LDP message type is used by a router to advertise its label bindings to neighbors?

Accepted Answer

Label Mapping message

Answer

LDP Label Mapping messages carry FEC-to-label bindings that a router distributes to its LDP peers.

Cisco ENCOR Practice Test

Cisco ENCOR Practice Test

Cisco ENCOR (MPLS) 4