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Guidelines for Configuring VLAN ID List-Bundled Logical Interfaces That Connect CCCs

For MX Series routers, you can bind a list of VLAN IDs to a logical interface, configure a Layer 2 VPN routing instance or Layer 2 circuit on the logical interface, and then use the logical interface to configure a circuit cross-connect (CCC) to another Layer 2 VPN routing instance or Layer 2 circuit.

A CCC allows you to configure transparent connections between two circuits so that packets from the source circuit are delivered to the destination circuit with, at most, the Layer 2 address being changed. You configure a CCC by connecting circuit interfaces of the same type. For more information, see Circuit and Translational Cross-Connects Overview.

Note:

The Junos OS supports binding of Ethernet logical interfaces to lists of VLAN IDs on MX Series routers only. For all other routers, you can bind an Ethernet logical interface to only a single VLAN ID or to a single range of VLAN IDs.

The following configuration guidelines apply to bundling lists of VLAN IDs to Ethernet logical interfaces used to configure CCCs:

Guidelines for Configuring Physical Link-Layer Encapsulation to Support CCCs

To enable a physical interface to support VLAN-bundled logical interfaces that you will use to configure a CCC, you must specify one of the following physical link-layer encapsulation types as the value of the encapsulation statement at the [edit interfaces interface-name] hierarchy level:

  • extended-vlan-ccc—For Ethernet interfaces with standard TPID tagging.

  • flexible-ethernet-services—For supported Gigabit Ethernet interfaces for which you want to configure multiple per-unit Ethernet encapsulations.

For more information about configuring the encapsulation on a physical interface, see .

Guidelines for Configuring Logical Link-Layer Encapsulation to Support CCCs

For VLAN-bundled logical interfaces that you use to configure a CCC, specific logical link-layer encapsulation types are used inside the circuits themselves.

Table 1 describes the logical link-layer encapsulation types used within circuits connected using VLAN-bundled logical interfaces of the same type.

Table 1: Encapsulation Inside Circuits CCC-Connected by VLAN-Bundled Logical Interfaces
Encapsulation Inside the Circuit Layer 2 Circuit Joined by Configuring an Interface-to-Interface CCC Connection
Layer 2 VPN Routing Instance Layer 2 Circuit
Syntax 
encapsulation-type (ethernet | ethernet-vlan);

encapsulation vlan-ccc;
Hierarchy Level 
[edit routing-instances routing-instance-name protocols l2vpn],
[edit logical-systems logical-system-name routing-instances routing-instance-name protocols l2vpn]																

[edit interfaces ethernet-interface-name unit logical-unit-number],
[edit logical-systems logical-system-name interfaces ethernet-interface-name unit logical-unit-number]
Usage Guidelines

See the Junos OS VPNs Library for Routing Devices.

See Configuring Interface Encapsulation on Logical Interfaces, Circuit and Translational Cross-Connects Overview, and Defining the Encapsulation for Switching Cross-Connects.
For a Single-Tag Logical Interface

The MX Series router automatically uses ethernet as the Layer 2 protocol used to encapsulate incoming traffic. Although the connection spans multiple VLANs, the VLANs are bundled and therefore can be encapsulated as a single VLAN.

NOTE: With ethernet encapsulation, the circuit signal processing does not check that the VLAN ID list is the same at both ends of the CCC connection.

Configure the MX Series router to use vlan-ccc as the logical link-layer encapsulation type.
For a Dual-Tag Logical Interface

Configure the MX Series router to use ethernet-vlan as the Layer 2 protocol to encapsulate incoming traffic.

With ethernet-vlan encapsulation, circuit signal processing checks that the VLAN ID list is the same at both ends of the CCC connection. If a VLAN ID list mismatch is detected, you can view the error condition in the show interfaces command output.

The MX Series router automatically uses vlan-ccc as the logical link-layer encapsulation type, regardless of the value configured.

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