RADWIN2000+SeriesUserManual Release4.2.40 15‐2
VLANTagging
15.4VLANTagging
VLANtaggingenablesmultiplebridgednetworkstotransparentlysharethesamephysical
networklinkwithoutleakageofinformationbetweennetworks:
IEEE802.1Qisusedastheencapsulationprotocoltoimplementthismechanismover
Ethernetnetworks.
15.4.1QinQ(DoubleTagging)forServiceProviders
QinQisusefulforServiceProviders,allowingthemtouseVLAN sinternallyintheir“transport
network”whilemixingEthernettrafficfromclientsthatarealreadyVLAN‐tagged.
Theoutertag(representingtheProviderVLAN)comesfirst,followedbytheinnertag.InQinQ
theEtherType=0x9100.VLANtagsmaybestackedthreeormoredeep.
Whenusingthistypeof“ProviderTagging ”youshouldkeepthefollowinginmind:
• UnderProviderTagging,thesystemdouble‐tagsegressframestowardstheProvider’s
network.ThesystemaddsatagwithaVLANIDandEtherType=0x9100toallframes,as
configuredbytheserviceprovider(ProviderVLANID).
• Thesystemalwaysaddstoeachframe,tagswithVLANIDandEtherT ype=0x9100.
Therefore,
• Foraframewithoutatag–thesystemwilladdatagwithVLANIDandEtherType=
0x9100sotheframewillhaveonetag
• ForaframewithaVLANtag–thesystemwilladdatagwithVLANIDandEtherType
=0x9100sotheframewillbedouble‐tagged
ForaframewithaVLANtagandaprovidertag–thesystemwilladdatagwithVLANIDand
EtherType=0x9100sotheframewillbetriple‐taggedandsoon.
Attheegressside,theRT‐B(HSU)removestheQinQtagwithEtherType=0x9100nomatter
whatthevalueofitsVLANID.
15.4.2VLANUntagging
VLANUntaggingmeanstheremovalofaVLANoraProvidertag.
15.4.3PortFunctionality
Ina2000+link,allVLANactivityisconfiguredandsupportedfromtheRT‐B(HSU).
Tothisend,VLANfunctionalityissupportedattheLANportoftheRT‐B(HSU).
TheRT‐B(HSU)LANportcanbeconfiguredtohandleEthernetframesattheingressdirection
(whereframesentertheRT‐B(HSU))andattheegressdirection(whereframesexittheRT‐
B(HSU)).