Specifications

Chapter 10 Traffic Shaping
Distributed Traffic Shaping
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Catalyst 4224 Access Gateway Switch Software Configuration Guide
OL-2031-02
Restrictions
FRTS applies only to Frame Relay PVCs and switched virtual circuits (SVCs).
Distributed Traffic Shaping
DTS provides a method of managing the bandwidth of an interface to avoid
congestion, to meet remote site requirements, and to conform to a service rate that
is provided on that interface.
DTS uses queues to buffer traffic surges that can congest a network and send the
data to the network at a regulated rate. This ensures that traffic will behave to the
configured descriptor, as defined by the CIR, Bc, and Be. With the defined
average bit rate and burst size that is acceptable on that shaped entity, you can
derive a time interval value.
Prerequisites
Distributed Cisco Express Forwarding (dCEF) must be enabled on the interface
before DTS can be enabled.
A policy map and class maps must be created before DTS is enabled.
How It Works
The Be size allows more than the Bc size to be sent during a time interval under
certain conditions. Therefore, DTS provides two types of shape commands:
average and peak. When shape average is configured, the interface sends no
more than the Bc size for each interval, achieving an average rate no higher than
the CIR. When the shape peak command is configured, the interface sends Bc
plus Be bits in each interval.
In a link layer network such as Frame Relay, the network sends messages with the
forward explicit congestion notification (FECN) or BECN if there is congestion.
With the DTS feature, the traffic shaping adaptive mode takes advantage of these
signals and adjusts the traffic descriptors, thereby regulating the amount of traffic
entering or leaving the interface accordingly.