Understanding QoS Configuration on the S- K- and 7100-Series

This section discusses the six components for configuring QoS and displaying QoS status on an S- K- and 7100-Series switch router:

• CoS Port-Type: Based upon the transmit queue (TxQ), Inbound Rate Limiting (IRL), and flood control resource capabilities of the ports in your system. Outbound Rate Limiting (ORL) is supported on the S- and K-Series. Knowledge of these capabilities is important when configuring queue behaviors. Port group membership and the port resources available are determined by port type.
• CoS Port Groups: Provide for the grouping of ports by the same class of service features and port type.
• CoS Port Resource Table: Enables the association of rate limiter and rate shaper values to a port.
• CoS Reference Mapping Table: Maps your defined index references used by the CoS settings table, to the physical queue and rate limiter settings created in the port-resource table:
  • TxQ, IRL, and ORL index references (S-, K-Series)
  • TxQ and IRL index references (7100-Series)
• CoS Settings Table: Used for CoS parameter assignment and contains the current settings for each class of service feature. Each class of service entry consists of an entry index, an 802.1p priority, an optional ToS value, a transmit queue reference, an IRL reference, and a flood control reference, and for the S- and K-Series an ORL reference.

  On the 7100-Series, flood control is not configurable. Flood control defaults to enabled for all CoS indexes and is applied when a resource is defined.

• CoS State: A global setting that must be enabled for a configured CoS to affect port behavior. When enabled, CoS state associated with a port supersedes current default or modified port-level controls for priority queue mapping, port rate limiting, and transmit queue. When disabled the port settings apply.

Note

It is recommended that you use Extreme Networks NetSight Policy Manager as an alternative to CLI for configuring policy-based CoS on Extreme Networks Series devices.

A policy discussion is outside the scope of this document and will be limited to the relevant configuration example commands. See Policy Configuration for a detailed policy discussion.

Numerous QoS values are associated with each other through reference. With the exception of 802.1p priority and ToS, CoS values are first mapped to a port group, which associates a CoS configuration with a port type. A port group has the following CoS parameters associated with it:

• Physical port(s)
• Strict priority or weighted fair queuing behavior
• Rate-limit setting(s)
• Rate-shaping setting(s)
• A port queue
• A port reference

Understanding how these parameters are first mapped to the port group and then to a TxQ or IRL reference is the key to understanding QoS configuration. Where appropriate, the task column in Class of Service CLI Configuration Command Summary identifies these mapping relationships.

See Determining CoS Port-Type and Configuring CoS Port Groups for a port group discussion.