tswtclmt - Time Sliding Window Three Conformance Level Meter


The Time Sliding Window Three Conformance level meter (tswtcl) meters a
traffic stream and determines the conformance level of its packets.

Packets are deemed to belong to one of the three levels, Red, Yellow or
Green, depending on the committed and peak rate.

The meter provides an estimate of the running average bandwidth. It takes
into account burstiness and smoothes out its estimate to approximate the
longer-term measured sending rate of the traffic stream.

The estimated bandwidth approximates the running average bandwidth of the
traffic stream over a specific window (time interval). tswtcl estimates
the average bandwidth using a time-based estimator. When a packet arrives
for a class, tswtcl re-computes the average rate by using the rate in the
last window (time interval) and the size of the arriving packet. The
window is then slid to start at the current time (the packet arrival
time). If the computed rate is less than the committed configuration
parameter, the packet is deemed Green; else if the rate is less than the
peak rate, it is Yellow; else Red. To avoid dropping multiple packets
within a TCP window, tswtcl probabilistically assigns one of the three
conformance level to the packet.


The tswtcl module exports global and per-class statistics through kstat:

Global statistics:

module: tswtclmt instance: <action id>
name: tswtclmt statistics class <action name>
green_bits <number of bit in green>
green_packets <number of packets in green>
red_bits <number of bits in red>
red_packets <number of packets in red>
yellow_bits <number of bits in yellow>
yellow_packets <number of packets in yellow>



64-bit module (SPARC only.)


dlcosmk(4IPP), dscpmk(4IPP), flowacct(4IPP), ipgpc(4IPP), ipqos(4IPP),
tokenmt(4IPP), ipqosconf(8)

RFC 2859, A Time Sliding Window Three Colour Marker (TSWTCM) W. Fang, N.
Seddigh, B. Nandy -- The Internet Society, 2000

September 29, 2004 TSWTCLMT(4IPP)