ZyXEL Communications SAM1316-22, Руководство пользователя

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SAM1316-22 User’s Guide
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H A P T E R
3 1
TLS PVC
This chapter shows you how to set up Transparent LAN Service (VLAN stacking, Q-
in-Q) on each port.
31.1 Transparent LAN Service (TLS) Overview
Transparent LAN Service (also known as VLAN stacking or Q-in-Q) allows a service
provider to distinguish multiple customers VLANs, even those with the same
(customer-assigned) VLAN ID, within its network.
Use TLS to add an outer VLAN tag to the inner IEEE 802.1Q tagged frames that
enter the network. By tagging the tagged frames (“double-tagged” frames), the
service provider can manage up to 4,094 VLAN groups with each group containing
up to 4,094 customer VLANs. This allows a service provider to provide different
services, based on specific VLANs, for many different customers.
A service provider’s customers may require a range of VLANs to handle multiple
applications. A service provider’s customers can assign their own inner VLAN tags
to traffic. The service provider can assign an outer VLAN tag for each customer.
Therefore, there is no VLAN tag overlap among customers, so traffic from different
customers is kept separate.
Before the SAM1316-22 sends the frames from the customers, the VLAN ID is
added to the frames. When packets intended for specific customers are received
on the SAM1316-22, the outer VLAN tag is removed before the traffic is sent.
31.1.1 TLS Network Example
In the following example figure, both A and B are Service Provider’s Network
(SPN) customers with VPN tunnels between their head offices and branch offices,
respectively. Both have an identical VLAN tag for their VLAN group. The service
provider can separate these two VLANs within its network by adding tag 37 to