ATM vs. IP/PPP: Why Frame Is Better Than Cells At The Network Edge

There has been much excitement and talk over the years about the appropriateness of ATM for all manner of telecommunications applications. Many white papers and articles asserted that ATM was the unifying platform that would enable service providers to deliver voice, data, and video to subscribers over a consolidated link, platform, and integrated access device (IAD). Though many of the arguments put forth in favor of ATM are true, today, it is well understood that ATM's one-size-fits-all approach sacrifices link efficiency and generates scalability problems for networks. The main intent of this white paper is to dispel the notion that ATM is the best alternative for edge networks. This paper will make two distinct points: * PPP is more efficient than ATM for the last mile or network edge-the portion of the network from the Central Office to the user CPE. Because of the inefficiencies of ATM, a subscriber with a T1/E1 frame-based service such as Frame Relay or PPP will experience degraded service when converted over to a symmetric DSL solution. * The architecture of ATM-based DSLAMs requires aggregation platforms that decrease operational efficiencies and increase operating costs associated with deploying the service.