Which of the following statements are TRUE regarding the PE device in a QoS enabled network? (Choose two)

Question

Options

• AA device that provides no differentiation between customer traffic flows.
• BA device that classifies and marks customer traffic.
• CA device that uses MPLS EXP bits to differentiate between traffic flows.
• DA device that creates macroflows towards the core from multiple customer sites.
• EA device that passes macroflows while optionally changing QoS markings.

• A
  3% (1)
• B
  86% (32)
• C
  3% (1)
• E
  8% (3)

Explanation

In MPLS VPN networks, the PE (Provider Edge) device sits at the boundary between a customer site and the provider core. B is correct because the PE's primary QoS role is to classify incoming customer traffic (microflows) and apply markings - such as setting MPLS EXP/TC bits - as traffic enters the provider network. D is correct because the PE aggregates traffic arriving from multiple customer CE devices into macroflows (MPLS LSPs) directed toward the core, effectively bundling many individual flows into a single forwarding path.

A is wrong because the PE explicitly does differentiate traffic - that's the whole point of deploying QoS at the edge. C is wrong because using MPLS EXP bits to make forwarding/scheduling decisions in the core is the role of the P (Provider Core) device, not the PE (which sets those bits but doesn't route based on them in the core). E is wrong for the same reason - passing macroflows while optionally re-marking EXP bits describes the P device's behavior as traffic transits the core.

Memory tip: Think of the PE as the "Policy Entry" point - it's where customer traffic enters the provider network, gets classified and marked, and gets bundled into macroflows. The P device is just a passthrough that uses those markings. PE = classify + aggregate; P = forward + optionally remark.

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