Cisco
352-001 · Question #220
352-001 Question #220: Real Exam Question with Answer & Explanation
The correct answer is B: Weighted RED. Cyclic congestion spikes with mostly TCP traffic indicate TCP global synchronization, where multiple flows back off and ramp up in unison. WRED breaks this synchronization by randomly dropping packets before the queue is full.
Question
Cyclic congestion spikes are causing your Telnet users to experience delays. Traffic analysis shows minimal use of UDP. Which technology can you deploy to mitigate the problem?
Options
- ACommitted Access Rate
- BWeighted RED
- CDeficit Round Robin
- DClass Based Weighted Fair Queuing
Explanation
Cyclic congestion spikes with mostly TCP traffic indicate TCP global synchronization, where multiple flows back off and ramp up in unison. WRED breaks this synchronization by randomly dropping packets before the queue is full.
Common mistakes.
- A. Committed Access Rate is a traffic policing mechanism that enforces rate limits but does not address TCP synchronization or smooth cyclic queue oscillation.
- C. Deficit Round Robin is a scheduling algorithm that fairly distributes bandwidth across flows but does not perform early random dropping and therefore does not mitigate TCP global synchronization.
- D. Class-Based Weighted Fair Queuing provides bandwidth guarantees per class and tail-drop queuing but does not break TCP synchronization - tail drop is actually a contributing cause of global synchronization.
Concept tested. WRED resolving TCP global synchronization congestion
Community Discussion
No community discussion yet for this question.