Technical Documentation

Configuring Layer 2 Protocol Tunneling on EX Series Switches (CLI Procedure)

Layer 2 protocol tunneling (L2PT) allows you to send Layer 2 protocol data units (PDUs) across a service provider network and deliver them to EX Series switches at a remote location. This feature is useful when you have a network that includes remote sites that are connected across a service provider network and you want to run Layer 2 protocols on switches connected across the service provider network.

Tunneled Layer 2 PDUs do not normally arrive at high rate. If the tunneled Layer 2 PDUs do arrive at high rate, there might be a problem in the network. Typically, you would want to shut down the interface that is receiving a high rate of tunneled Layer 2 PDUs so that the problem can be isolated. You do so using the shutdown-threshold statement. However, if you do not want to completely shut down the interface, you can configure the switch to drop tunneled Layer 2 PDUs that exceed a certain threshold using the drop-threshold statement.

There are no default settings for drop-threshold and shutdown-threshold. If you do not specify these thresholds, then no thresholds are enforced. As a result, the switch tunnels all Layer 2 PDUs regardless of the speed at which they are received, although the number of packets tunneled per second might be limited by other factors.

You can specify a drop threshold value without specifying a shutdown threshold value, and you can specify a shutdown threshold value without specifying a drop threshold value. If you specify both threshold values, then the drop threshold value must be less than or equal to the shutdown threshold value. If the drop threshold value is greater than the shutdown threshold value and you try to commit the configuration, the commit will fail.

Note: If the switch receives untagged Layer 2 control PDUs to be tunnelled, then you must configure the switch to map untagged (native) packets to an L2PT-enabled VLAN. Otherwise, the untagged Layer 2 control PDU packets are discarded. For more information, see Understanding Q-in-Q Tunneling on EX Series Switches and Configuring Q-in-Q Tunneling (CLI Procedure).

To configure L2PT on an EX Series switch:

  1. Because L2PT operates under the Q-in-Q tunneling configuration, you must enable Q-in-Q tunneling before you can configure L2PT. Enable Q-in-Q tunneling on VLAN customer-1:

    [edit]
    user@switch# set vlans customer-1 dot1q-tunneling
  2. Enable L2PT for the Layer 2 protocol you want to tunnel, on the VLAN:
    • To enable L2PT for a specific protocol (here, STP):

      [edit]
      user@switch# set vlans customer-1 dot1q-tunneling layer2-protocol-tunneling stp
    • To enable L2PT for all supported protocols:

      [edit]
      user@switch# set vlans customer-1 dot1q-tunneling layer2-protocol-tunneling all
  3. (Optional) Configure the drop threshold:

    Note: If you also configure the shutdown threshold, ensure that you configure the drop threshold value to be less than or equal to the shutdown threshold value. If the drop threshold value is greater than the shutdown threshold value and you to try to commit the configuration changes, the commit will fail.


    [edit]
    user@switch# set vlans customer-1 dot1q-tunneling layer2–protocol-tunneling stp drop-threshold 50
  4. (Optional) Configure the shutdown threshold:

    Note: If you also configure the drop threshold, ensure that you configure the shutdown threshold value to be greater than or equal to the drop threshold value. If the shutdown threshold value is less than the drop threshold value and you to try to commit the configuration changes, the commit will fail.


    [edit]
    user@switch# set vlans customer-1 dot1q-tunneling layer2–protocol-tunneling stp shutdown-threshold 100

    Note: Once an interface is disabled, you must explicitly reenable it using the clear ethernet-switching layer2-protocol-tunneling error command. Otherwise, the interface remains disabled.


Published: 2009-10-13