User manual

Table Of Contents
ZXR105900/5200SeriesUserManual(EthernetSwitchingVolume)
Assumeports1,2and3belongtothesameVLAN,whiletheother
portsbelongtootherVLANs,thenframesreceivedonport1are
broadcasttoports2and3onlywhiletheyarenotpassedtoany
otherport.WhenauserinaVLANmovestoanewlocation,itno
longerbelongstotheoriginalVLANunlesstheuserisassignedto
thatVLANagain.
VLANTag
ItispossibletotransmitservicesofseveralVLANsoverasingle
linkifaframecarriesinformationaboutitsnativeVLANwhilebeing
passedthroughanetwork.IEEE802.1Qimplementsthisfunction
throughattachingaVLANtagtotheEthernetframe.
AVLANtagisafour-bytelongnumber,anditcomesafterthe
sourceMACaddressandbeforethelength/typeeldinanEthernet
frame.Figure1showstheVLANtagformat.
FIGURE1VLANTAGFORMAT
VLANtagisappliedtocross-switchVLANs,whenthelinkbetween
switchesisusuallycalledatrunk.VLANtagallowsVLANscross
severalswitchestobecreatedthroughoneormoretrunks.When
theportsconnectingtheseswitchesreceiveataggedframe,the
portscanjudgewhichVLANtheframebelongstobasedonthe
VLANtag.
Each802.1QportisallocatedadefaultVLANID,calledPVID.Un-
taggedframesreceivedonaportisconsideredbelongingtothe
defaultVLAN,andthenbroadcastedinthatVLAN.
ZXR105900/5200supportsIEEE802.1Qtag.
VLANLinkType
ZXR105900/5200portssupportthefollowinglinks:
1.Accesslink
Itconnectsdevices(suchasworkstation)thatcannotiden-
tifyVLANtagstotheVLANswitchport.Ittransmitsuntagged
framesonlytoasingleVLAN.
2.Trunklink
2CondentialandProprietaryInformationofZTECORPORATION