Vlan Stacking - ZyXEL Communications GS3700 Series User Manual

This chapt er shows you how t o configure VLAN st acking on your Swit ch. See t he chapt er on VLANs
for m ore background inform at ion on Virt ual LAN
22.1 VLAN Stacking Overview
A service provider can use VLAN st acking t o allow it t o dist inguish m ult iple cust om ers VLANs, even
t hose wit h t he sam e ( cust om er- assigned) VLAN I D, wit hin it s net work.
Use VLAN st acking t o add an out er VLAN t ag t o t he inner I EEE 802.1Q t agged fram es t hat ent er t he
net work. By t agging t he t agged fram es ( " double- t agged" fram es) , t he service provider can m anage
up t o 4,094 VLAN groups wit h each group cont aining up t o 4,094 cust om er VLANs. This allows a
service provider t o provide different service, based on specific VLANs, for m any different
cust om ers.
A service provider 's cust om ers m ay require a range of VLANs t o handle m ult iple applicat ions. A
service provider 's cust om ers can assign t heir own inner VLAN t ags on port s for t hese applicat ions.
The service provider can assign an out er VLAN t ag for each cust om er. Therefore, t here is no VLAN
t ag overlap am ong cust om ers, so t raffic from different cust om ers is kept separat e.
22.1.1 VLAN Stacking Example
I n t he following exam ple figure, bot h A and B are Service Provider 's Net work ( SPN) cust om ers wit h
VPN t unnels bet ween t heir head offices and branch offices respect ively. Bot h have an ident ical VLAN
t ag for t heir VLAN group. The service provider can separat e t hese t wo VLANs wit hin it s net work by
adding t ag 37 t o dist inguish cust om er A and t ag 48 t o dist inguish cust om er B at edge device 1 and
t hen st ripping t hose t ags at edge device 2 as t he dat a fram es leave t he net work.
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VLAN Stacking

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