Cisco 642-883 Online Practice Questions and Exam Preparation

Cisco 642-883 Online Questions & Answers

• Question 171:

  Which OSPF feature allows a router with redundant route processors to maintain its OSPF state and adjacencies across planned and unplanned RP switchovers and does this by checkpointing state information from OSPF on the active RP to the standby RP? This feature does not require the OSPF neighbor to support graceful restart.

  A. NSR
  B. NSF
  C. BFD
  D. MTR
  E. SDR
  A. NSR

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  Continuous Forwarding An important aspect of high availability is maintenance of traffic forwarding, even in the case of control-plane switchovers. Cisco IOS XR Software has several built-in features that can provide continuous forwarding, including RSP stateful switchover (SSO), Nonstop Forwarding (NSF), Graceful Restart, and NSR.

  NSF: Cisco IOS XR Software supports forwarding without traffic loss during a brief outage of the control plane through signaling and routing protocol implementations for Graceful Restart extensions as standardized by the IETF. In addition to standards compliance, this implementation has been compatibility tested with Cisco IOS Software and third-party operating systems.

  Graceful Restart: This control-plane mechanism ensures high availability by allowing detection and recovery from failure conditions while preserving NSF services. Graceful Restart is a way to recover from signaling and control-plane failures without affecting the forwarding plane. Cisco IOS XR Software uses this feature and a combination of check pointing, mirroring, RSP redundancy, and other system resiliency features to recover prior to timeout and avoid service downtime as a result of network reconvergence. NSR: This feature allows for the forwarding of data packets to continue along known routes while the routing protocol information is being refreshed following a processor switchover.

  NSR maintains protocol sessions and state information across SSO functions for services such as Multiprotocol Label Switching (MPLS) VPN. TCP connections and the routing protocol sessions are migrated from the active RSP to the standby RSP after the RSP failover without letting the peers know about the failover. The sessions terminate locally on the failed RSP, and the protocols running on the standby RSP reestablish the sessions after the standby RSP goes active, without the peer detecting the change. You can also use NSR with Graceful Restart to protect the routing control plane during switchovers. The Cisco IOS XR Operating System provides system resiliency through a comprehensive set of high-availability features including modularity, process restart, fault handling, continuous forwarding, and upgradability.

• Question 172:

  A network engineer implements IS-IS authentication in a router. When the engineer implements the same password on the router's peer, the output below is displayed with the debug IS-IS authentication information:

  * Nov 6 13:23:46:967: ISIS-Authinfo: No auth TLV found in received packet

  Which option is one reason for this output?

  A. Authentication was not configured on the router that sent the update.
  B. The length of the password is not the same.
  C. There is an error with the NET address in one of the routers.
  D. The authentication is set the same way, but the password does not match.
  A. Authentication was not configured on the router that sent the update.

• Question 173:

  Refer to the exhibit.

  

  Which two configuration options can be used to optimize the IS-IS network scenario? (Choose two.)

  A. Change the R1 and R2 IS type to Level 2.
  B. Change the R1 and R2 IS type to Level 1.
  C. Change the gi0/0 interface IS-IS circuit type on R1 and R2 to Level 2 only.
  D. Change the gi0/1 interface IS-IS circuit type on R1and R2 to Level 1.
  E. Change the IS type for all the routers to Level-1-2.
  F. Change the IS-IS network type for all the routers to point-to-point.
  C. Change the gi0/0 interface IS-IS circuit type on R1 and R2 to Level 2 only.
  D. Change the gi0/1 interface IS-IS circuit type on R1and R2 to Level 1.

• Question 174:

  Which three BGP configuration groupings are supported on Cisco IOS XR Software? (Choose three.)

  A. peer-group
  B. af-group
  C. bgp-group
  D. session-group
  E. neighbor-group
  F. as-group
  B. af-group
  D. session-group
  E. neighbor-group