The Internet Engineering Task Force (IETF) has defined protocols in the area of Layer Two Tunneling Protocol—Version 3 (L2TPv3) and Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture, as defined in RFC 3193, RFC 3931, RFC 3985, RFC 4591, and RFC 4719. The L2TPv3 pseudo wires may support multiple types of layer two encapsulations or “Pseudowire Types”, including protocols similar in packet format to IEEE 802.3, virtual LAN tagging protocols such as IEEE 802.1Q, IEEE 802.1ad, and IEEE 802.1ah, as well as Point-to-Point Protocol (PPP), Frame Relay, and other layer 2 technologies.
As defined in the standard track protocols above, the Pseudowire Types including Ethernet, VLAN, PPP, or Frame Relay, etc are encapsulated into “L2TPv3” to emulate a single layer 2 tunnel link between exactly two endpoints.
Enabling L2TPv3 on cable modems (CM), embedded multimedia terminal adapters (E-MTA), cable modem routers (CM-R), cable modem with Circuit Emulation Service (CES), cable modem with IPSec or Firewall and/or similar DOCSIS Customer Premise Equipment (D-CPE) will allow L2TPv3 IP packets to be encapsulated into Data Over Cable Service Interface Specification (DOCSIS) data frames for two-way data transmission in a cable system. Devices with this capability are referred to herein as “L2TPv3 enabled DOCSIS CPE”, or simply “Enhanced CPE”.