Cisco Certified Support Technician (CCST) NetworkingIP ServicesMedium
A network administrator needs to ensure that voice over IP (VoIP) traffic receives preferential treatment over other data traffic on a congested link. Which QoS mechanism is used to prioritize specific types of traffic by placing it into different queues based on its classification?
- ALink Fragmentation and Interleaving (LFI)
- BCongestion Management
- CPolicing
- DTraffic Shaping
Show answer & explanationAnswer & explanation
Correct answer: B. Congestion Management
Congestion management, primarily through queuing mechanisms, is used to prioritize specific types of traffic when a link becomes congested. It determines which packets are transmitted first.
Why the other options are wrong
- A. LFI is a technique to reduce serialization delay for small, time-sensitive packets over slow links, not a general queuing mechanism.
- C. Policing drops or re-marks traffic that exceeds a configured rate, it doesn't prioritize in queues.
- D. Traffic shaping buffers excess traffic to smooth out the flow, not necessarily prioritize within queues.
QoS Congestion Management
A QoS mechanism that handles traffic when a network link becomes congested, typically by using queuing algorithms to prioritize certain traffic types.
- Manages traffic flow during peak usage.
- Uses queuing to determine transmission order.
- Examples include FIFO, Weighted Fair Queuing (WFQ), Class-Based Weighted Fair Queuing (CBWFQ).
Memory trick: When there's a jam (congestion), a good manager directs traffic.