Overview and Purpose

Dashboard-managed Differentiated Services Code Point (DSCP), quality of service (QoS), and scheduling provide a direct way to preserve application performance during WAN congestion. Traffic-shaping rules identify traffic by application, application category, hostname, port, IP range, or local network, then preserve or apply a DSCP marking. The router uses the resulting marking to place traffic into one of four fixed WAN egress service classes and applies low-latency or weighted scheduling automatically.

Default operation: WAN egress QoS scheduling is enabled by default on supported routers. No action is required to enable the Realtime, High, Normal, and Low service classes or their scheduling behavior. Use Dashboard traffic-shaping rules to preserve or apply DSCP markings for selected traffic.

Traffic Classification and Scheduling

• Classification: A rule can identify applications, application categories, hostnames, ports, IP ranges, and local networks as traffic enters through supported LAN interfaces. Traffic matching any definition is subject to the rule.

• Rule order: Enabled default rules are evaluated before custom rules. Custom rules are evaluated in the order displayed in Dashboard.

• DSCP marking: A rule can preserve the packet's existing DSCP marking or apply a supported DSCP marking. The resulting marking determines the WAN egress service class.

• Scheduling: Dashboard maps traffic into Realtime, High, Normal, and Low service classes and applies their scheduling parameters automatically.

Egress Service Class	DSCP Markings	Congestion Treatment
Realtime	32 (CS4), 34 (AF41), 36 (AF42), 38 (AF43), 40 (CS5), 44 (VOICE-ADMIT), 46 (EF), and 48 (CS6)	Low-latency priority service, limited to 50% of the WAN egress policy bandwidth during congestion
High	24 (CS3), 26 (AF31), 28 (AF32), and 30 (AF33)	Remaining-bandwidth ratio 4
Normal	Any user-traffic DSCP marking not matched by Realtime, High, or Low	Remaining-bandwidth ratio 2
Low	0 (CS0/DF; default)	Remaining-bandwidth ratio 1

Scheduling Model

CBWFQ, LLQ, and DRR: Class-Based Weighted Fair Queueing (CBWFQ) provides WAN egress scheduling. The Realtime class uses Low Latency Queueing (LLQ) for strict-priority service and is limited to 50% of the shaped WAN bandwidth during congestion. After Realtime traffic is serviced, Deficit Round Robin (DRR) distributes the remaining bandwidth among the High, Normal, and Low classes using relative weights of 4:2:1. These weights are not fixed bandwidth percentages.

Prerequisites and Limitations

Licensing Requirements

This capability is included in base Essentials licensing for Dashboard-enabled devices.

Hardware Requirements

A supported Dashboard-enabled IOS XE secure router is required. See Onboarding IOS XE Based Secure Routers into Dashboard for supported models.

Dashboard Requirements

The router must be onboarded into Dashboard and use Cloud as its Configuration Source before traffic-shaping rules are configured.

• A Dashboard administrator with configuration write access is required to add, edit, remove, reorder, or save traffic-shaping rules. Read-only administrators can view the configuration.

Firmware Requirements

DSCP, QoS, and scheduling are available on devices running IOS XE 26.2.1 or later. A reboot is not required when traffic-shaping rules are changed. Allow 1–2 minutes after saving for changes to take effect.

Limitations

• A maximum of eight traffic-shaping rules is supported. When enabled, the four default rules count toward this limit.

Configuration

For the Dashboard workflow used to create, edit, reorder, and save traffic-shaping rules, see SD-WAN and Traffic Shaping.

IOS XE traffic-shaping controls: For Dashboard-managed IOS XE secure routers, use the rule Definition to identify traffic and DSCP tagging to preserve or apply the marking that selects the WAN egress service class. Bandwidth limit displays Ignore network per-client limit (unlimited) and is not configurable.