Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A company has implemented a new VoIP system, and users are reporting dropped calls and poor audio quality, characterized by choppiness and delays. The network administrator suspects network congestion is causing these issues. Which QoS mechanism should be configured on the network devices to prioritize VoIP traffic and ensure its quality?
- ATraffic Shaping
- BCongestion Management (Queuing)
- CLink Fragmentation and Interleaving (LFI)
- DTraffic Policing
Show answer & explanationAnswer & explanation
Correct answer: B. Congestion Management (Queuing)
Congestion Management, specifically queuing mechanisms like Low Latency Queuing (LLQ) or Weighted Fair Queuing (WFQ), is designed to prioritize critical traffic like VoIP during periods of congestion, ensuring it gets preferential treatment and reducing delay and jitter.
Why the other options are wrong
- A. Traffic Shaping buffers excess traffic to smooth out bursts, which can introduce delay and is not ideal for real-time VoIP.
- C. LFI is a technique for interleaving small, time-sensitive packets with larger packets over slow links, but it's part of a broader QoS strategy, not the primary mechanism for prioritizing during congestion.
- D. Traffic Policing drops or remarks traffic that exceeds a rate limit, which can exacerbate VoIP issues if packets are dropped.
QoS Congestion Management
QoS mechanisms that deal with traffic when a link becomes congested, typically by using queuing algorithms to prioritize certain types of traffic over others.
- Queuing is a primary component.
- Ensures preferential treatment for critical traffic.
- Examples: LLQ, WFQ, CBWFQ.
Memory trick: Queues keep VoIP clear, like a VIP line at a concert.