Vlan Advantages - Siemens RUGGEDCOM ROS User Manual

Chapter 5
Setup and Configuration
always adds an extra tag (called an outer tag) on top of the frame's original VLAN tag (called an inner tag). The
outer tag VID is the PVID of the frame's ingress edge port. This means that traffic from an individual customer is
tagged with their unique VID and is thus segregated from other customer's traffic.
Within the service provider network, switching is based on the VID in the outer tag.
When double-tagged frames leave the service provider network, they egress a QinQ-enabled port of another
switch. The switch strips the outer tag while associating the frames with the VID extracted from it before stripping.
Thus, the frames are switched to appropriate edge ports ( i.e. customers).
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Figure 79: Using QinQ
1. Customer 1 (PVID is X)
NOTE
QinQ can only be enabled on one switch port at a time.
NOTE
Some switch models only support QinQ if all edge ports are configured with the same PVID. In this
case, a dedicated switch must be assigned to each customer.
Section 5.2.1.11

VLAN Advantages

The following are a few of the advantages offered by VLANs.
Traffic Domain Isolation
VLANs are most often used for their ability to restrict traffic flows between groups of devices.
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2. Customer 2 (PVID is Y) 3. Network Service Provider Infrastructure
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4. Switch 5. QinQ
VLAN Advantages