TSWTCLMT(4IPP) IP Quality of Service Modules TSWTCLMT(4IPP)

NAME

tswtclmt - Time Sliding Window Three Conformance Level Meter

DESCRIPTION

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.

STATISTICS

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>

FILES

/kernel/ipp/sparcv9/tswtclmt

64-bit module (SPARC only.)

SEE ALSO

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)