Cisco Systems 4500 About VLAN Mapping

25-7
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 25 Configuring 802.1Q Tunneling, VLAN Mapping, and Layer 2 Protocol Tunneling About VLAN Mapping
Switch(config-if)# exit
Switch(config)# vlan dot1q tag native
Switch(config)# end
Switch# show dot1q-tunnel interface gigabitethernet2/7
Port
-----
LAN Port(s)
-----
Gi2/7
Switch# show vlan dot1q tag native
dot1q native vlan tagging is enabled globally
About VLAN Mapping
In a typical deployment of VLAN mapping, you want the service provider to provide a transparent
switching infrastructure that treats customers’ switches at the remote location as a part of the local site.
This allows customers to use the same VLAN ID space and run Layer 2 control protocols seamlessly
across the provider network. In such scenarios, we recommend that service providers do not impose their
VLAN IDs on their customers.
One way to establish translated VLAN IDs (S-VLANs) is to map customer VLANs to service-provider
VLANs (called VLAN ID translation) on trunk ports connected to a customer network. Packets entering
the port are mapped to a service provider VLAN (S-VLAN) based on the port number and the packet’s
original customer VLAN-ID (C-VLAN).
Service providers’s internal assignments might conflict with a customer’s VLAN. To isolate customer
traffic, a service provider could decide to map a specific VLAN into another one while the traffic is in
its cloud.
Deployment Example
In Figure 25-4, the service provider provides Layer 2 VPN service to two different customers, A and B.
The service provider separates the data and control traffic between the two customers and from the
providers’ own control traffic. The service provider network must also be transparent to the customer
edge devices.