Manual

Software User Guide 46
Network Tab
0‐Default:
BandGroup0‐G900G1800W2100W800
BandGroup1‐G1900G850W1900W850
1‐Europe/RestoftheWorld:
BandGroup0‐G900G1800W2100W800
BandGroup1‐G1900G850W1900W850
2‐NorthAmerica:
BandGroup0‐G1900G850W1900W850
BandGroup1‐G900G1800W2100W800
3‐Australia:
BandGroup
0‐G900G1800W850W2100W800
BandGroup1‐G1900G850W1900
4‐Japan:
BandGroup0‐G900G1800W2100W800
BandGroup1‐G1900G850W1900W850
SelectCellularNetworkSpeed:Selecttheconnectionspeedtobeusedforthecellularmodemconnectionfromthe
dropdownlistprovided.Possiblevaluesinclude:Auto,HighandLow.TherecommendedsettingforthisfieldisAuto.
CellularMTU:EntertheMTUsiz eyoudesiretouse.Incomputernetworking,the
maximumtransmissionunit(MTU)
ofacommunicationsprotocolofalayeristhesize(inbytes)ofthelargestprotocoldataunitthatthelayercanpass
onwards.MTUparametersusuallyappearinassociationwithacommunicationsinterface(NIC,serialport,etc.).Stan‐
dards(Ethernet,forexample)canfix thesize
ofanMTU;orsystems(suchaspoint‐to‐pointseriallinks)maydecide
MTUatconnecttime.AlargerMTUbringsgreaterefficiencybecauseeachpacketcarriesmoreuserdatawhileproto‐
coloverheads,suchasheadersorunderlyingper‐packetdelays,remainfixed;theresultinghigherefficiencymeans
a
slightimprovementinbulkprotocolthroughput.AlargerMTUalsomeansprocessingoffewerpacketsforthesame
amountofdata.Insomesystems,per‐packet ‐processingcanbeacriticalperformancelimitation.
However,thisgainisnotwithoutsomedownside.Largepacketscanoccupyaslowlinkforsome
time,causinggreater
delaystofollowingpacketsandincreasinglagandminimumlatency.Forexample,a1500‐bytepacket,thelargest
allowedbyEthernetatthenetworklayer(andhenceovermostoftheInternet),tiesupa14.4kmodemforaboutone
second.
Therecommendedsettingforthisfieldis
1500.
SyncTime:Thisoptionwillattempttotakethelocaltimeasreportedbythecellulartower,andsettheunit’ssystem
timetomatch.TherecommendedsettingforthisfieldisYes,unlessanothermethodoftimeSync,suchasNTPis
beingused.
ChooseConnectionBehavior:InPersistent
mode,theunitwillalwaysattempttomaintainacellularconnectionwith
thecarrier’snetwork.InOn‐Demandmode,theconnectiontothecellularnetworkwillonlybeattemptedwhenpack‐
etsaredestinedtoleavethewirelessinterface.Inaddition,afteraperiodofIdleTime,theconnectionwillterminate.
Persistentmodehasthepotentialtousemorebandwidthinalimiteddataplanmeantforfallback.Forthisreason,
On‐Demandiscommonlychosenforanenvironmentusinganethernetconnectionasaprimaryinterface,whileIP
Fallbackisusedtobringupthesecondarywirelessconnectionasabackup.
Moderncellularconnectionsuseidle
statesinon‐boardradiostooftennegatetheneedforanOn‐demandoption.