Do You Need a Broadband Remote Access Server?: Functionality and Trade-Offs of Using Smart DSLAMs and MSANs

Overview

There are many misconceptions about the role of the DSL Forum's Broadband Network Gateway (BNG), better known as a Broadband Remote Access Server (BRAS) or Broadband Services Router (BSR). The BSR has evolved significantly from its original role of terminating PPPoX sessions. Proponents talk about enhanced subscriber management capabilities, while detractors claim that all needed functions can be done by a smart Digital Subscriber Line Access Multiplexer (DSLAM) or MSAN (Multiservice Access Node). There are several functions that must be performed to successfully support broadband traffic. This paper describes the key functions that may need to be implemented by the smart edge device, either the MSAN or the BSR.