Radwin 2000 D+ - Page 162

RADWIN2000D+UserManual Release3.6.00 15‐2
QinQ(DoubleTagging)forServiceProviders Chapter15
IEEE802.1Qisusedastheencapsulation protocoltoimplementthismechanismover
Ethernetnetworks.
15.4.1QinQ(DoubleTagging)forServiceProviders
QinQisusefulforServiceProviders,allowingthemtouseVLANsinternallyintheir“transport
network”whilemixingEthernettrafficfromclientsthatarealreadyVLAN‐tagged.
Theoutertag(representingtheProviderVLAN)comesfirst,followedbytheinnertag.InQinQ
theEtherType=0x9100.VLANtagsmaybestackedthreeormoredeep.
Whenusingthistypeof“Provider Tagging ”youshouldkeepthefollowinginmind:
• UnderProviderTagging,thesystemdouble‐tagsegressframestowardstheProvider’s
network.ThesystemaddsatagwithaVLANIDandEtherType=0x9100toallframes,as
configuredbytheserviceprovider(ProviderVLANID).
• Thesystemalwaysaddstoeachframe,tagswithVLANIDandEtherT ype=0x9100.
Therefore,
• Foraframewithoutatag–thesystemwilladdatagwithVLANIDandEtherT ype=
0x9100sotheframewillhaveonetag
• ForaframewithaVLAN tag–thesystemwilladdatagwithVLANIDandEtherType
=0x9100sotheframewillbedouble‐tagged
ForaframewithaVLANtagandaprovidertag–thesystemwilladdatagwithVLANIDand
EtherType=0x9100sotheframewillbetriple‐taggedandsoon.
Attheegressside,theRT‐B(HSU)removestheQinQtagwithEtherT ype=0x9100nomatter
whatthevalueofitsVLANID.
15.4.2VLANUntagging
VLANUntaggingmeanstheremovalofaVLANoraProvidertag.
15.4.3PortFunctionality
InaRADWIN2000D+link,allVLANactivityisconfigure dandsupportedfromtheRT‐B(HSU).
Tothisend,VLANfunctionalityissupportedattheLANportoftheRT‐B(HSU).
TheRT‐B(HSU)LANportcanbeconfiguredtohandleEthernetframesattheingressdirection
(whereframesentertheRT‐B(HSU))andattheegressdirection(whereframesexittheRT‐
B(HSU)).