Configure Layer 2.5 VPNs
Layer 2.5 VPNs are an extension to Layer 2 VPNs. The main difference is that Layer 2.5 VPNs are not required to have the same media on both ends of the connection. In general, Layer 2.5 VPNs combine the capabilities of TCC with Layer 2 VPNs.
Layer 2.5 VPNs support the same media types as TCC: ATM, Cisco HDLC, Ethernet, extended VLAN, Frame Relay, and PPP. The only traffic type that is currently supported is IPv4. Also, IS-IS adjacencies cannot be formed across a TCC connection because they use Open Systems Interconnection (OSI) framing.
Although not covered in this manual, you can also use TCC in conjunction with Layer 2 circuits to connect two CE sites that use different Layer 2 protocols. You can use these so-called Layer 2.5 circuits as an alternative to Layer 2.5 VPNs. For more information about Layer 2 circuits, see Layer 2 Circuits or the JUNOS Internet Software VPNs Configuration Guide.
To configure Layer 2.5 VPNs, complete the following tasks:
- Configure the Encapsulation on Interfaces Participating in the Layer 2.5 VPN
- Configure the Layer 2.5 VPN
To view an example of a Layer 2.5 VPN, go to the following sections: