ECS4100 Series Web Management Guide-R07

Chapter 5 | VLAN Configuration
L2PT Tunneling
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4. Click Apply.
Figure 95: Adding an Interface to a QinQ Tunnel
L2PT Tunneling
When Layer 2 Protocol Tunneling (L2PT) is not used, protocol packets (e.g., STP) are
flooded to 802.1Q access ports on the same edge switch, but filtered from 802.1Q
tunnel ports. This creates disconnected protocol domains in the customer’s
network.
L2PT can be used to pass various types of protocol packets belonging to the same
customer transparently across a service provider’s network. In this way, normally
segregated network segments can be configured to function inside a common
protocol domain.
Command Usage
◆ L2PT encapsulates protocol packets entering ingress ports on the service
provider’s edge switch, replacing the destination MAC address with a
proprietary MAC address (for example, the spanning tree protocol uses 10-12-
CF-00-00-02), a reserved address for other specified protocol types (as defined
in IEEE 802.1ad – Provider Bridges), or a user-defined address. All intermediate
switches carrying this traffic across the service provider’s network treat these
encapsulated packets in the same way as normal data, forwarding them to the
tunnel’s egress port. The egress port decapsulates these packets, restores the
proper protocol and MAC address information, and then floods them onto the
same VLANs at the customer’s remote site (via all of the appropriate tunnel
ports and access ports
4
connected to the same metro VLAN).
◆ The way in which L2PT processes packets is based on the following criteria –
(1) packet is received on a QinQ uplink port, (2) packet is received on a QinQ
access port, or (3) received packet is Cisco-compatible L2PT (i.e., as indicated by
a proprietary MAC address).
4. Access ports in this context are 802.1Q trunk ports.