Network Router User Manual

Global Positioning System (GPS)
Rev 3.0B Feb.08 88
• Grouped‐Reportshelduntilthetotalisequalorgreater
than*PPSNFMwhichsetsthepacketsizeofgrouped
reports.
Store and Forward Reliable Mode
TheStoreandForwardReliableModeallowsthePinPoint‐Eto
ensureallmessagesarereceivedbytheserverevenifthe
connectionbetweenthemgoesdownforaperiodoftime(s uch
whenavehiclepassesthroughalocationwherethecellular
signalisweakornon‐existent).
WithReliableMode,*PPSNFR,enabled,thePinPoint‐Ewill
transmitasequencenumber(1to127)aspartofapacketof
messages(maycontainoneormorereports).Toreduce
overhead,theserveronlyacknowledgesreceiptofevery
eighthpacket.ThePinPoint‐Econsidersthat8a“window”of
outstandingpackets.
IfthePinPoint‐Edoesn’treceiveacknowledgementfora
“window”,themodemwillPINGtheserverwithamessage
containingthesequencenumbersofthefirstandlastpackets
thathaven’tbeenacknowledged.ThePinPoint‐Ewillcontinue
untiltheserveracknowledgesreceipt.WhenthePinPoint‐E
receivestheacknowledgement,it
willadvanceits“window”to
thenextgroup.
WhenthePinPoint ‐Eisfirstpoweredon(orreset),itwillsend
aSetWindowmessagetosyncupwiththeserverforthe
current“window”.
Ontheotherside,iftheserverreceivesanoutofsequence
packet,itwillsendamessagetothemodemnotingthemissing
sequenceandthePinPoint‐Ewillretransmit.
Figure 9-11: AceManager : PinPoint - *PPSNFR, *PPMAXRETRIES
SimpleReliableModewill‘giveup’afteraconfigured
number,*PPMAXRETRIES ,ofat temptsanddiscardmessages
thatcannotbetransmittedorreceivedafterthatnumberof
tries.
Sending Reports Based on an Interval
YoucanconfigurethePinPoint‐Etosendreportsbasedona
timeintervaland/oronthemovementofavehicle(basedon
it’spositionfromonetimetothenext).