Specifications

VLAN Support on Enterasys Switches
March 15, 2011 Page 7 of 20
•From2through4093forstackableandstandaloneswitches
Thisrangeisbasedonthefollowingrules:
• VID0isthenullVLANID,indicatingthatthetagheaderintheframecontainspriority
informationratherthanaVLANidentifier.ItcannotbeconfiguredasaportVLANID(PVID).
• VID
1isdesignatedthedefaultPVIDvalueforclassifyingframesoningressthrougha
switchedport.Thisdefaultcanbechangedonaper‐portbasis.
• VID4095isreservedbyIEEEforimplementationuse.
• VID4094isreservedonstackableandstandaloneswitches. 
VLAN Types
EnterasysswitchessupporttrafficclassificationforthefollowingVLANtypes:
Static and Dynamic VLANs
AllVLANsonanEnterasysswitcharecategorizedasbeing eitherstaticordynamic.StaticVLANs 
arethosethatareexplicitlycreatedontheswitchitself,persistentlyremainingaspartofthe
configuration,regardlessofactualusage.DynamicVLANs,ontheotherhand,arenotnecessarily
persistent.Theirpresencerelieson
theimplementationofGVRPanditseffectonegress
membershipasdescribedin“GARPVLANRegistrationProtocol(GVRP)Support”onpage8.
Port-Based VLANs
Port‐basedVLANs areconfiguredbyassociatingswitchportstoVLANsintwoways:first,by
manipulatingtheportVLANID(PVID);andsecond,byaddingtheportitselftotheegresslistof
theVLANcorrespondingtothePVID.AnytrafficreceivedbyaportisassociatedtotheVLAN

identifiedbytheportʹsPVID.Byvirtueofthisassociation,thistrafficmayegresstheswitchonly
onthoseportslistedontheVLANʹsegresslist.Forexample,givenaVLANnamed“Marketing,”
withanIDvalueof6,bychangingthePVIDvaluesofports1through
3to6,andaddingthose
portstotheegresslistoftheVLAN,weeffectivelyrestrictthebroadcastdomainofMarketingto
thosethreeports.Ifabroadcastframeisreceivedonport1,itwillbetransmittedoutports2and3
only.Inthissense,VLANmembershipis
determinedbythelocationoftrafficingress,andfrom
theperspectiveoftheaccesslayer—whereusersaremostcommonlylocated—egressisgenerally
untagged.
Policy-Based VLANs
RatherthanmakingVLANmembershipdecisionssimplybasedonportconfiguration,each
incomingframecanbeexaminedbytheclassificationenginewhichusesamatch‐based logicto
assigntheframetoadesiredVLAN.Forexample,youcouldsetupapolicywhichdesignatesall
e‐mailtrafficbetweenthe
managementofficersofacompanytoaspecificVLANsothatthistraffic
isrestrictedtocertainportionsofthenetwork.Withrespecttonetworkusage,theadministrative
advantagesofpolicyclassificationwouldbeapplicationprovisioning,acceptableusepolicy,and
distributionlayerpolicy.Alloftheseprovisionsmayinvolvesimultaneous
utilizationofinter‐
switchlinksbymultipleVLANs,requiringparticularattentiontotagged,forbidden,and
untaggedegresssettings.
Notes: Each VLAN ID in a network must be unique. If you enter a duplicate VLAN ID, the Enterasys
switch assumes you intend to modify the existing VLAN.