QoS

Quality of Service, the toolkit for keeping latency-sensitive traffic flowing predictably across crowded networks. Articles tagged QoS cover classification and marking (DSCP, CoS), MQC, queueing (LLQ, CBWFQ), policing, shaping, and voice and video treatment in SD-WAN and wireless.

8 posts

QoS

QoS in Modern Networks: SD-WAN, Cloud, and Application-Aware Steering

QoS in 2026 is application-aware steering at the SD-WAN edge plus local queueing per tunnel. Why DSCP stops being honored at administrative boundaries, and how SD-WAN path conditioning compensates.

Apr 25, 2026 7 min read

QoS

Voice and Video QoS on Cisco IOS XE

Voice and video are the use cases QoS exists for. Latency and jitter budgets, DSCP markings, IP phone trust, LLQ configuration, codec bandwidth math, and wireless voice via WMM.

Apr 25, 2026 7 min read

QoS

QoS Queueing, Policing, and Shaping Compared

LLQ, CBWFQ, policing, and shaping each do something different. The three primitives, when to use which, hierarchical shaping for sub-rate WAN handoffs, and the production patterns.

Apr 25, 2026 7 min read

QoS

QoS Classification, Marking, and Trust Boundaries

Classification and marking at the trust boundary are the foundation of every QoS deployment. The patterns (untrusted access ports, conditional trust for IP phones, explicit MQC marking) and the discipline that makes them work.

Apr 25, 2026 7 min read

QoS

Cisco MQC (Modular QoS CLI): The Operator's Walkthrough

The Cisco MQC three-construct model (class-map, policy-map, service-policy) covers every QoS feature on IOS, IOS XE, and IOS XR. The grammar, common actions, hierarchical policies, and verification.

Apr 25, 2026 6 min read

QoS

DSCP and IP Precedence Explained Byte by Byte

DSCP is the 6-bit Layer 3 marking that drives modern QoS. The byte format, the standardized PHBs (CS, AF, EF), Cisco's DSCP-to-CoS-to-MPLS-EXP mapping, and trust boundary discipline.

Apr 25, 2026 6 min read