Cisco
352-001 · Question #136
352-001 Question #136: Real Exam Question with Answer & Explanation
The correct answer is B: Use Selective Address Tracking and match the peers.. For multihop eBGP, Selective Address Tracking and Fast Peering Session Deactivation are specifically designed to detect peer loss quickly without excessive control-plane overhead.
Question
Your company requires two diverse multihop External Border Gateway Protocol peerings to a partner network. Which two methods would you use to improve lost peer detection? (Choose two.)
Options
- AUse Bidirectional Forwarding Detection for the peers.
- BUse Selective Address Tracking and match the peers.
- CUse subsecond keepalives for the peers.
- DUse subsecond hold timers for the peers.
- EUse Fast Peering Session Deactivation for the peers.
- FUse subsecond minimum route advertisement Interval timers for the peers.
Explanation
For multihop eBGP, Selective Address Tracking and Fast Peering Session Deactivation are specifically designed to detect peer loss quickly without excessive control-plane overhead.
Common mistakes.
- A. BFD for multihop eBGP requires explicit multihop BFD configuration and is less reliable across diverse forwarding paths; SAT and Fast Peering Session Deactivation are the preferred Cisco-recommended tools for this scenario.
- C. Subsecond keepalives significantly increase control-plane traffic and CPU processing on both peers, adding network burden rather than efficiently detecting failure.
- D. Subsecond hold timers cause BGP sessions to tear down at the slightest delay or packet loss, leading to excessive instability and route churn rather than reliable failure detection.
- F. The minimum route advertisement interval (MRAI) controls how frequently BGP sends routing updates to peers and has no effect on detecting whether a peer session itself is lost.
Concept tested. BGP fast peer loss detection with SAT and Fast Peering Session Deactivation
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