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    Example: Configuring S-VLAN Tunnels for Layer 2 Services over MPLS

    The example in this section illustrates how to configure S-VLAN tunnels for Ethernet layer 2 services over MPLS.

    Requirements

    This example uses the following software and hardware components:

    • JunosE Release 7.1.0 or higher-numbered releases
    • E Series router (ERX7xx models, ERX14xx models, the ERX310 router, the E120 router, or the E320 router)
    • ASIC-based line modules that support Fast Ethernet or Gigabit Ethernet

    Overview of Configuring S-VLAN Tunnels for Ethernet Layer 2 Services over MPLS

    When you configure Ethernet layer 2 services over MPLS, you can create a special type of S-VLAN called an S-VLAN tunnel that uses a single interface to tunnel traffic from multiple VLANs across an MPLS network. The S-VLAN tunnel enables multiple VLANs, each configured with a unique VLAN ID tag, to share a common S-VLAN ID tag when they traverse an MPLS network.

    Advantages of using S-VLAN Tunnels

    Using S-VLAN tunnels provides an easier and faster way to configure Ethernet layer 2 services over MPLS than using standard S-VLANs. For example, consider the network configuration shown in Figure 1.

    Figure 1: S-VLAN Tunnels for Ethernet Layer 2 Services over MPLS

    S-VLAN Tunnels for Ethernet Layer 2 Services
over MPLS

    In this example, traffic from three VLAN subinterfaces must traverse the MPLS network. To accomplish this using standard S-VLANs, you issue the following commands to configure three separate S-VLANs with the same S-VLAN ID value and different VLAN IDs, as follows:

    host1(config-if)#svlan id 33 10 host1(config-if)#svlan id 33 20 host1(config-if)#svlan id 33 30

    By contrast, using an S-VLAN tunnel achieves the same result, but requires you to issue only a single svlan id command with the keyword any in place of the VLAN ID value. For example, the following command creates a single interface that tunnels traffic from VLANs configured with an S-VLAN ID of 33 and any VLAN ID to the same destination across the MPLS network. In effect, this command tunnels traffic from all three VLANs shown in Figure 1.

    host1(config-if)#svlan id 33 any

    Interface Stacking

    When you configure Ethernet layer 2 services over MPLS using S-VLAN tunnels, the only interface that you can stack over an S-VLAN tunnel is an MPLS tunnel, which you configure using the MPLS tunneling command (mpls-relay or route interface) that is appropriate for your configuration. Attempting to configure any other interface type—such as IP, MPLS (nontunnel), or PPPoE—over the S-VLAN tunnel causes the router to generate an error and reject the configuration as invalid.

    For details about configuring MPLS and layer 2 services over MPLS, see:

    • Configuring MPLS in JunosE BGP and MPLS Configuration Guide
    • Configuring Layer 2 Services over MPLS in JunosE BGP and MPLS Configuration Guide

    Configuring S-VLAN Tunnels for Ethernet Layer 2 Services over MPLS

    This section uses the sample network topology shown in Figure 1 to illustrate the steps for configuring S-VLAN tunnels for Ethernet layer 2 services over MPLS.

    To configure S-VLAN tunnels for Ethernet layer 2 services over MPLS:

    1. Specify a Fast Ethernet, Gigabit Ethernet, or 10-Gigabit Ethernet port.
      host1(config)#interface fastEthernet 4/0
    2. Specify VLAN as the encapsulation method to create the VLAN major interface.
      host1(config-if)#encapsulation vlan
    3. Create a VLAN subinterface.
      host1(config-if)#interface fastEthernet 8/1.1
    4. Create the S-VLAN tunnel. This interface tunnels traffic from VLANs configured with an S-VLAN ID of 33 and any VLAN ID to the same destination across the MPLS network.
      host1(config-if)#svlan id 33 any
    5. Assign an S-VLAN Ethertype.
      host1(config-if)#svlan ethertype 8100
    6. Create the MPLS tunnel interface using the appropriate MPLS tunneling command for your configuration. For example:
      host1(config-if)#route interface tunnel mpls:tunnel3 45

      For complete instructions on configuring the MPLS tunnel, see Configuring Layer 2 Services over MPLS in JunosE BGP and MPLS Configuration Guide.

    7. Repeat Steps 1 through 6 using unique values to configure the S-VLAN tunnel and MPLS tunnel interfaces on the remote E Series router. For example:
      host2(config)#interface fastEthernet 3/1host2(config-if)#encapsulation vlanhost2(config-if)#interface fastEthernet 3/1.1 host2(config-if)#svlan id 83 any host2(config-if)#svlan ethertype 88a8host2(config-if)#route interface tunnel mpls:tunnel2 45

    Published: 2014-08-14