2 Digital subscriber line VDSL2
2.15 Protocol structure of VDSL2 connections

Interconnection between the subscriber and the ISP service provider can be in general built on a different protocol architectures. Nowadays, we mainly use standard Ethernet, Point-to-Point Protocol and a family of protocols based on TCP/IP.

The protocol structure of VDSL2 connections for data transmission in PTM mode.

The transmission of IP packets is handled by using of PPP (Point-to-Point Protocol) at VDSL2 connection in PTM mode, and these IP packets are encapsulated into Ethernet frames (PPP over Ethernet). In place of the termination of the PPP connection is performed authentication, authorization, accounting, allocation of IP addresses within the PPP connection, aggregation of data flows and other services. Those services meet the broadband access server BRAS (Broadband Access Server) of access provider in the aggregation point. BRAS from the server, the data is also transported the end user to the Internet or to individual service providers through a VPN (Virtual Private Network). This entire solution is referred to as variant PTA (PPP Terminated Aggregation).