Manual

Software User Guide 52
Network Tab
EnterRemoteGateway:EntertheIPAddressforthegatewaydeviceinthefieldprovided.Thisfieldis onlyavailable
whenObtainNetworkAddressesviaDHCPhasbeensettoNO.ThisfieldisrequiredifUseRemoteGatewayas
DefaultRouteissettoYes.
Agatewayisadevice
(typicallyarouter)usedtogainaccesstoanothernetwork.Forexample,ifadeviceisattached
toaLANwhosenetworkaddressis192.168.1.0withanetmaskof255.255.255.0,thenitcancommunicatedirectly
withanyotherdeviceonthatnetworkwitharangeofaddressesof192.168.1.1through
192.168.1.254(with
192.168.1.255reservedforbroadcast).Anaddressoutsideofthatrangeisonadifferentnetworkwhichwouldneed
toaccessedindirectlythrougharouterandthatrouterwouldbethegatewaytothenetworkonwhichtheremote
targetdeviceresides,sotocommunicatewithitwouldmeansending
andreceivingviathegatewaydevice.Thisalso
requireseitherdefiningastaticroute(definedthroughtheNetwork→StacRoutesscreen)viathatgatewayormak‐
ingitthedefaultroute(bysettingUseRemoteGatewayasDefaultRoutetoYes
.
YourNetworkAdministratorshouldbeabletoprovideanappropriatevalue.Theaddressmustbeonewithinthevalid
rangeforthenetwork.
EnterMaximumTransmissionUnit(MTU):EnterthedesiredMTUsize.Incomputernetworking,themaximumtrans‐
mission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).Standards(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protocoloverheads,suchasheadersorunderlyingper‐packetdelays,remainfix ed;theresultinghigher
efficiencymeansaslightimprovementsinbulkprotocolthroughput.AlargerMTUalsomeansprocessingof
fewer
packetsforthesameamountofdata.Insomesystems,per‐pack et‐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layer(andhenceovermostof
theInternet),tiesupa14.4kmodemforaboutonesec‐
ond.Therecommendedsettingis1500.
InterfaceAliases:Sub‐interfacingisessentiallythesegmentingofasinglewire,orport,intomultipleIPnetworks.Instead
ofsubnettingandrouting,youcancreateasub‐interfaceandthensetitup
asyouwouldastandardEthernetinterface.
Toconfigureasub‐interface:
• ClickontheAddbuttonandthefollowingpop‐upwindowwillappear: