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Cisco ONS 15310-CL and Cisco ONS 15310-MA Ethernet Card Software Feature and Configuration Guide R8.5
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Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling on the ML-Series Card
Virtual private networks (VPNs) provide enterprise-scale connectivity on a shared infrastructure, often
Ethernet-based, with the same security, prioritization, reliability, and manageability requirements of
private networks. Tunneling is a feature designed for service providers who carry traffic of multiple
customers across their networks and are required to maintain t he VLAN and Layer 2 protocol
configurations of each customer without impacting the traffic of other cu stomers. The ML-Series cards
support IEEE 802.1Q tunneling (QinQ) and Layer 2 protocol tunneling.
This chapter contains the following sections:
• Understanding IEEE 802.1Q Tunneling, page 8-1
• Configuring IEEE 802.1Q Tunneling, page 8-4
• Understanding VLAN-Transparent and VLAN-Specific Services, page 8-6
• VLAN-Transparent and VLAN-Specific Services Configuration Example, page 8-7
• Understanding Layer 2 Protocol Tunneling, page 8-9
• Configuring Layer 2 Protocol Tunneling, page 8-9

Understanding IEEE 802.1Q Tunneling

Business customers of service providers often have specific requirements for VLAN IDs and the number
of VLANs to be supported. The VLAN ranges required by different customers in the same
service-provider network might overlap, and traffic of customers through the infrastructure might be
mixed. Assigning a unique range of VLAN IDs to each customer woul d restrict customer configurations
and could easily exceed the IEEE 802.1Q specification VLAN limit of 4096.
Using the IEEE 802.1Q tunneling (QinQ) feature, service providers can use a single VLA N to support
customers who have multiple VLANs. Customer VLAN IDs are preserved and traffic from different
customers is segregated within the service-provider infrastructure even when they appear to be on the
same VLAN. The IEEE 802.1Q tunneling expands VLAN space by using a VLAN-in-VLAN hierarchy
and tagging the tagged packets. A port configured to support IEEE 802.1Q tunneling is called a tunnel
port. When you configure tunneling, you assign a tunnel port to a VLAN that is de dicated to tunneling.
Each customer requires a separate VLAN, but that VLAN supports all of the customer’s VLANs.