In which of the following scenarios is the egress port scheduler useful? (Choose two)

Question

Options

• AA customer is complaining that his VoIP traffic is being dropped even though it is sending the
• BA customer is complaining that his VoIP traffic is being dropped even though it is sending the
• CA commercial builder has requested numerous dot1Q epipes, VPRNs, and VPLS services to a
• DAn equipment manufacturer has requested a NULL epipe service that will transparently pass

• A
  75% (18)
• B
  17% (4)
• D
  8% (2)

Explanation

Options A and C are correct because the egress port scheduler operates at the port level to manage how traffic leaves the device - making it essential in two distinct scenarios: when latency-sensitive traffic like VoIP is being starved by competing flows at the egress port (A), and when multiple services (dot1Q epipes, VPRNs, VPLS) share a single egress port and need bandwidth arbitration across service queues (C). In scenario A, the egress port scheduler can apply strict priority or weighted scheduling to ensure VoIP packets are served before bulk traffic, preventing drops caused by queue contention at the port level. In scenario C, it governs how the aggregate bandwidth of the port is distributed across many services, which is exactly the multi-service sharing problem it was designed for.

Why B is wrong: The beginning of B mirrors A, but the implied scenario likely involves a problem solvable at the ingress (policing/shaping) rather than egress scheduling - or the traffic is genuinely exceeding its committed rate, where egress scheduling cannot help.

Why D is wrong: A NULL epipe passes traffic transparently with no QoS treatment, meaning the egress port scheduler's queuing and prioritization mechanisms are bypassed by design - applying one here would contradict the service's purpose.

Memory tip: Think "Priority + Port-sharing" - reach for the egress port scheduler when you need to prioritize sensitive traffic (VoIP) or partition bandwidth among many co-located services on the same physical port.

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