Quality of Service & Traffic Management Flashcards
7 cards from real ACA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Quality of Service & Traffic Management flashcards as text
What is the key difference between traffic shaping and traffic policing?
Answer: Shaping buffers excess packets to smooth traffic; policing drops or re-marks excess packets immediately
Traffic shaping delays excess packets in a buffer to conform to the rate limit, producing a smooth output; policing immediately drops or re-marks packets that exceed the rate.
Which queuing mechanism uses multiple queues with configurable weights to distribute bandwidth proportionally?
Answer: Weighted Round Robin (WRR)
Weighted Round Robin (WRR) cycles through multiple queues and services each according to its configured weight, guaranteeing proportional bandwidth distribution.
On Aruba AOS-CX switches, where are QoS policies most commonly applied to enforce traffic prioritization?
Answer: On ingress and egress interfaces using QoS profiles
On Aruba AOS-CX, QoS schedules and policies are applied to physical or LAG interfaces at ingress (classification/remarking) and egress (scheduling/queuing).
What is 'jitter' in the context of network QoS for real-time applications?
Answer: The variation in packet arrival delay over time
Jitter is the variation (inconsistency) in packet delay over time; excessive jitter degrades real-time applications like VoIP and video conferencing because packets arrive unevenly.
Which DSCP Assured Forwarding (AF) class is recommended for interactive video conferencing traffic?
Answer: AF41 (DSCP 34)
AF41 (DSCP 34) is the recommended marking for interactive video traffic per RFC 4594, providing high-priority assured forwarding with low drop probability.
In Aruba wireless networks, which WMM access category maps to voice traffic?
Answer: AC_VO (Voice)
AC_VO (Voice) is the highest-priority WMM access category, mapped to 802.1p CoS values 6 and 7, providing the lowest latency and jitter for voice traffic.
What QoS action can Aruba switches perform on incoming traffic that is already marked with a DSCP value at the network edge?
Answer: They can trust, re-mark, or reclassify the DSCP marking using QoS policies
Aruba switches can be configured to trust incoming DSCP markings from trusted devices, or to reclassify and re-mark traffic using QoS policies when traffic arrives from untrusted sources.