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Configuring 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. They support IPv4, IS-IS, and MPLS traffic types, but do not support IPv6 traffic.

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.