Which of the following BEST describes a SAP when regarding QoS?

Question

Options

• AA point in the network where EXP bits can be mapped to one of eight predefined FCs, each one
• BA logical point in a service tunnel where all of customer traffic is aggregated.
• CA point at which the initial classification of customer traffic occurs.
• DA point in the network where QoS parameters are discarded in favor of lower-level hardware
• EA point in the network where traffic flows from multiple different services are queued together,

• A
  6% (2)
• C
  91% (31)
• D
  3% (1)

Explanation

Option C is correct because a SAP (Service Access Point) is the customer-facing interface point where traffic enters a provider's network - making it the natural location for initial traffic classification. At ingress, the SAP examines packet headers (DSCP, 802.1p bits, etc.) to assign traffic to the appropriate Forwarding Class and queue.

Why the distractors are wrong:

• A describes MPLS EXP/TC bit-to-FC mapping, which occurs at transit/label-switching points, not specifically at the SAP definition itself.
• B confuses a SAP with an SDP (Service Distribution Point), which is the tunnel endpoint used to aggregate customer traffic across the provider core.
• D is the opposite of reality - the SAP is where QoS begins, not where it is discarded.
• E describes a shared queuing model (like a network queue on a core interface), not the SAP concept.

Memory tip: Think of SAP as the "Stamp And Process" point - it's the network's first handshake with customer traffic, where it gets stamped with a classification before traveling deeper into the service infrastructure.

No community discussion yet for this question.