Implementing Continuous Forwarding During Control Plane Failure | Cisco IOS XR Software | Exam 400-201 | CCIE Service Provider

Technologies for Continuous Forwarding During Control Plane Failure

Question

A network engineer is responsible for implementing a solution with Cisco IOS XR Software that insures continuous forwarding during a control plane failure.

Which two technologies should the engineer consider? (Choose two.)

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D. E.

CE.

http://www.cisco.com/c/en/us/td/docs/routers/crs/software/crs_r4-3/mpls/configuration/guide/b_mpls_cg43xcrs/b_mpls_cg43crs_chapter_01.html#task_1129395

To ensure continuous forwarding during a control plane failure, the engineer should consider the following technologies:

  1. IP FRR (Fast ReRoute): IP FRR is a Cisco IOS XR technology that provides a mechanism to protect against link or node failure in a network. IP FRR uses alternate paths to bypass the failed link or node and provide uninterrupted service to the user traffic. IP FRR is based on Multiprotocol Label Switching (MPLS) Fast Reroute (FRR) and can be used in MPLS and non-MPLS networks.

  2. NSR (Non-Stop Routing): NSR is a Cisco IOS XR technology that provides uninterrupted routing during a control plane switchover. NSR allows the standby control plane to take over the routing functions from the active control plane without disrupting the forwarding of user traffic. NSR reduces the convergence time and ensures that the control plane failure does not impact the user traffic.

Therefore, options B (IP FRR) and E (NSR) are the correct answers.

TE FRR (Traffic Engineering Fast ReRoute) is a technology that provides protection against link or node failure in a MPLS network. It is not relevant to the question.

Graceful Restart is a mechanism that allows the restarting router to continue forwarding traffic during a control plane restart. However, it is not sufficient to ensure continuous forwarding during a control plane failure.

BFD (Bidirectional Forwarding Detection) is a protocol that detects faults in the forwarding path between two routers. It is not directly related to ensuring continuous forwarding during a control plane failure.