
Quality of Service
QoS Advanced Mode
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
364
20
•
•
•
•
•
Overview
Frames that match an ACL and permitted entrance are implicitly labeled with the name of the
ACL that permitted their entrance. Advanced mode QoS actions can then be applied to these
flows.
In QoS advanced mode, the device uses policies to support per flow QoS. A policy and its
components have the following characteristics and relationships:
•
A policy contains one or more class maps.
•
A class map defines a flow with one or more associating ACLs. Packets that match
only ACL rules (ACE) in a class map with Permit (forward) action are considered
belonging to the same flow, and are subjected to the same quality of services. Thus, a
policy contains one or more flows, each with a user defined QoS.
•
The QoS of a class map (flow) is enforced by the associating policer. There are two
type of policers, single policer and aggregate policer. Each policer is configured with a
QoS specification. A single policer applies the QoS to a single class map, and thus to a
single flow, based on the policer QoS specification. An aggregate policer applies the
QoS to one or more class maps, and thus one or more flows. An aggregate policer can
support class maps from different policies.
The 2 Rate 3 Color (2R3C) feature is supported on the device. In this feature, every
policer has two thresholds. If the first threshold is reached, a user-configured Exceed
action is performed. If the second threshold is reached, a user-configured Violate
action is performed (see
).
•
Per flow QoS are applied to flows by binding the policies to the desired ports. A policy
and its class maps can be bound to one or more ports, but each port is bound with at
most one policy.