Filter
Top Products
Policy-Map Commands
12-96 Configuring Quality of Service
Syntax of the “no” Form
Thenoformofthiscommandsetstheconstanttothedefaultvalueof9:
no random-detect exponential-weighting-constant
Mode
Policy‐MapClassconfiguration:XSR(config-pmap-c-<xx>)#
Example
ThefollowingexampleenablesWREDandsetstheweightconstantto(1/2)^5:
XSR(config)#policy-map wred
XSR(config-pmap<wred>)#class a
XSR(config-pmap-c<a>)#random-detect dscp-based
XSR(config-pmap-c<a>)#random-detect exponential-weighting-constant 5
random-detect precedence
ThiscommandsetsWeightedRandomEarlyDetect(WRED)theminimumandmaximum
thresholdandmaximumdropprobabilityvaluesforaIPprecedencevalue.
ThedefaultWREDmaximumdropprobability(MaxP)is1/10andthedefaultmaximumthreshold
(MaxTh)is40forallIPprecedencevalues.Thedefaultminimumthreshold
iscalculatedfrom
MaxThbasedonfollowingformula:
MinTh=(1/2‐precvalue/16)xMaxTh
Tochangethedefaultsetting,usethe
random-detect precedence default command.Bydoing
so,allIPprecedencewillsharethesamevaluesexceptthosewhichwereexplicitlyconfigured
with
random-detect precedence.ThissettingisusefulifWREDshouldoperateasRED.To
reverttotheoriginaldefaultsetting,enter
no random-detect precedence default.
Syntax
random-detect precedence prec-value min-thres max-thres [mark-prob]default
Syntax of the “no” Form
ThenoformofthiscommandrevertsWREDparameterstothedefaultforaprecedencevalue:
no random-detect precedence prec-value
prec-value
Precedencevalue,rangingfrom0to7withthekeyworddefault.
min-thres
Minimumnumberofpacketsinthequeue,rangingfrom1to4096,
beyondwhichtheXSRrandomlydropspackets.
max-thres
Maximumnumberofpacketsinthequeue,rangingfrom1to4096,
beyondwhichtheXSRdropsallpackets.
mark-prob
Markprobabilitydenominator.Liklihoodofqueuedpacketstobe
droppedwhentheirnumberexceedingtheminimumlimitisbetween0
and(1/mark‐prob).Range:1to65,536.