Explanation/Reference:
Explanation:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t2/feature/guide/gtl2tpv3.html#wp1040784 The Layer 2 Tunnel Protocol Version 3 feature expands on Cisco support of the Layer 2 Tunnel Protocol Version 3 (L2TPv3). L2TPv3 is an Internet Engineering Task Force (IETF) l2tpext working group draft that provides several enhancements to L2TP for the capability to tunnel any Layer 2 payload over L2TP.
Specifically, L2TPv3 defines the L2TP protocol for tunneling Layer 2 payloads over an IP core network using Layer 2 virtual private networks (VPNs). Benefits of this feature include the following:
*L2TPv3 simplifies deployment of VPNs
*L2TPv3 does not require Multiprotocol Label Switching
*L2TPv3 supports Layer 2 tunneling over IP for any payload
http://www.cisco.com/en/US/products/ps6646/products_ios_protocol_option_home.html Cisco Any Transport over MPLS (AToM) is a solution for transporting Layer 2 packets over an MPLS backbone. It enables Service Providers to supply connectivity between customer sites with existing data link layer (Layer 2) networks via a single, integrated, packet-based network infrastructure: a Cisco MPLS network. Without separate networks that each have network management environments, Service Providers can deliver Layer 2 connections over an MPLS backbone.
Cisco AToM provides a common framework to encapsulate and transport supported Layer 2 traffic types over an MPLS network core. Service Providers can use a single MPLS network infrastructure to offer connectivity for supported Layer 2 traffic and for IP traffic in Layer 3 VPNs.