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
Which DSCP value represents Expedited Forwarding (EF), typically used for VoIP traffic?
Answer: DSCP 46
DSCP EF is encoded as decimal 46 (binary 101110) and is reserved for low-latency, low-jitter, low-loss traffic such as VoIP.
What is the valid range of 802.1p Class of Service (CoS) values in an 802.1Q tag?
Answer: 0–7
802.1p CoS uses a 3-bit Priority Code Point (PCP) field in the 802.1Q tag, providing 8 possible values from 0 to 7.
Which queuing mechanism guarantees a minimum bandwidth to each class while still allowing unused bandwidth to be shared?
Answer: Class-Based Weighted Fair Queuing (CBWFQ)
CBWFQ assigns guaranteed minimum bandwidth to each defined class and distributes any remaining bandwidth proportionally among classes.
What does WRED stand for and what problem does it solve?
Answer: Weighted Random Early Detection — prevents tail-drop congestion by proactively dropping packets before queues fill
WRED (Weighted Random Early Detection) randomly drops packets before queues are completely full, preventing TCP global synchronization and favoring lower-priority traffic for drops.
In Aruba AOS-CX switches, what is the default number of QoS queues available per port?
Answer: 8
Aruba AOS-CX switches support 8 egress queues per port, allowing granular traffic prioritization aligned to 802.1p CoS or DSCP values.
What DSCP value is assigned to Best Effort (BE) traffic, which receives no special QoS treatment?
Answer: DSCP 0
DSCP 0 (Default Forwarding / DF) represents Best Effort traffic and receives no guaranteed service — it is the baseline with no QoS marking.
Which Aruba feature allows network administrators to apply QoS policies based on identified application type rather than just IP/port?
Answer: Application Visibility and Control (AVC) with AppRF
Aruba's Application Visibility and Control (AVC) using AppRF identifies applications through deep packet inspection and enforces QoS policies based on application type.