ADTRAN Total Access 5000 - Page 117

Section 4, EoCu Provisioning - Create an EFM Bonding Group
65K510DEP08-1A 4-13
•Ethernetframesbetween513and1024bytes,inclusive:
%Utilization=(FrameSize)/(FrameSize+16)x(64/65)
•Ethernetframes1025bytesorlarger:
%Utilization=(FrameSize)/(FrameSize+24)x(64/65)
TheequationsaboveassumethattheNetVantaisnotaddinganextratagto
thecustomer
traffic(ie.whenthecustomertrafficistagged,andthecustomeredgetagisnotbeing
preserved).Inanycasewherethecustomertagispreserve d(themostlikelyscenario),andthe
NetVanta838issimplystackingtheprovisionedserviceprovidertag(s‐tag)tothecustomer
tag
(ifpresent),thecalculationmustaccountfortheadditional4bytesforthes‐tag,asfollows:
•ForEthernetframes512bytesorsmaller:
%Utilization=(FrameSize)/(FrameSize+12)x(64/65)
•ForEthernetframesbetween513and1024bytes,inclusive:
%Utilization=(FrameSize)/(FrameSize
+20)x(64/65)
•Ethernetframes1025bytesorlarger:
%Utilization=(FrameSize)/(FrameSize+28)x(64/65)
TodeterminetheEFMbondinggroupbandwidththatneedstobeprovisionedsothatthe
customerʹscommissionedrateisprovided,dividethecustomerratebythispercentage:
RequiredEFM
GroupRate=(CustomerCommissionedRate)/(%Utilization.
Followingareexamplecalculationsforcustomerthroughputpercentage,givenafixedframe
size,assumingtheNetVanta838isaddingaVLANtag:
•For64byteEthernetframes(worstcasescenario):
%Utilization=(64)/(64+12)x(64/65)=82.9%
•For
an8Mbpsbondinggroup,theactualthroughputwouldbe:
8Mbpsx.829=6.632Mbps
•Ifacustomerissolda4Mbpsservice,therequiredEFMgroupsizecalculationwouldbe:
(4Mbps)/(.829)=4.825Mbps
•For1500byteEthernetframes:
%Utilization=(1500)/(1500+
28)x(64/65)=96.7%
•Foran8Mbpsbondinggroup,theactualthroughputwouldbe:
8Mbpsx.967=7.736Mbps
•Ifacustomerissolda4Mbpsservice,therequiredEFMgroupsizecalculationwouldbe:
(4Mbps)/(.967)=4.137Mbps
Anotherpointofreferenceisthe
EFMbondinggrouputilizationpercentagethatisseen
assuminguniformdistributionofframesizes,from64to1518bytes.Thisvalueis96.0%
assumingtheserviceproviderVLANtagisbeingaddedtothe customertraffic.Assuming
uniformtrafficsize,theEFMgroupwouldneedtobeafactorof1.042
greaterthanthe
commissionedcustomerratetoprovidethefullcustomerrate.
Theserviceproviderisbestsuitedtodecidewhattrafficmodelitwantstousefornetwork
planning,butthetoolsaboveshouldallowthemtosuitablydeterminetheEFMGroup
bandwidthneededtoprovidethecustomerʹsfull
trafficrate.