class of service

Pre-Alpha. This page describes behavior that may change.

Class-of-Service (CoS) in Ze maps the 3-bit IEEE 802.1p Priority Code Point (PCP) in 802.1Q VLAN headers to internal priorities and back. The feature has two layers: named profiles defined under class-of-service, and per-interface or per-unit bindings that reference those profiles.

The cos plugin owns this surface. Removing the plugin removes all QoS configuration from interfaces.

Named profiles

Profiles live under class-of-service { ieee-802.1p { ... } }. Each profile defines an ingress map (PCP to priority) and an egress map (priority to PCP). PCP and priority values are 0 through 7.

class-of-service {
    ieee-802.1p voip {
        ingress {
            pcp 5 { priority 7; }
            pcp 0 { priority 0; }
        }
        egress {
            priority 7 { pcp 5; }
            priority 0 { pcp 0; }
        }
    }
}

Unmapped PCP values keep priority 0 on ingress. Unmapped priorities are sent with PCP 0 on egress.

Interface binding

Reference a profile on an interface to apply it to all VLAN units on that interface:

interface {
    ethernet eth0 {
        class-of-service voip;
        unit 0 {
            vlan-id 100;
        }
        unit mgmt {
            vlan-id 200;
            class-of-service none;
        }
    }
}

All units inherit the interface-level profile. A unit can override it with a different profile name, or opt out entirely with none.

Inline QoS maps

Instead of referencing a named profile, a unit can define its maps inline. Inline maps and a profile reference are mutually exclusive on the same unit.

interface {
    ethernet eth0 {
        unit 0 {
            vlan-id 100;
            ingress-qos-map 5 { priority 7; }
            egress-qos-map 7 { pcp 5; }
        }
    }
}

Dynamic per-subscriber CoS via RADIUS

For L2TP/PPPoE subscribers, the CoS profile can be assigned dynamically at session establishment through RADIUS attributes:

Source	Attribute	Format
Filter-Id (11)	cos:<profile-name>	Selects a named 802.1p profile for the subscriber's access VLAN
Cisco-AVPair (vendor 9)	subscriber:sub-qos-policy-in, subscriber:sub-qos-policy-out	CoS profile name
Juniper ERX (vendor 4874)	Ingress-Policy-Name, Egress-Policy-Name	CoS profile name
Nokia (vendor 6527)	Alc-Subscriber-QoS-Override	CoS profile name
Huawei (vendor 2011)	HW-Subscriber-QoS-Profile	CoS profile name
MikroTik (vendor 14988)	Mikrotik-Rate-Limit	Shaper rate extraction (not CoS profile)

Ze cos: Filter-Id takes priority over vendor-specific attributes. Unknown vendor IDs are silently ignored.

The profile is applied on session-up. Mid-session CoA (Change of Authorization) updates are supported: a new cos: Filter-Id in a CoA message switches the active profile. On session-down, the subscriber's QoS state reverts.

VPP support

When the VPP interface backend is active, CoS maps are applied through the VPP qos-record (ingress) and qos-mark (egress) APIs instead of netlink VLAN QoS map ioctls.

CLI

show class-of-service          # List all registered profiles with their maps
show subscriber detail <id>    # Includes CoS profile when the cos plugin is loaded

See also

• Interfaces for the interface configuration surface.
• L2TP/PPP for the subscriber session model and RADIUS integration.
• Plugins for the plugin catalogue.
• Traffic Control for per-interface queueing disciplines.

Adapted from the cos plugin YANG schema and source code.