Next-generation access network architectures for video, voice, interactive gaming, and other emerging applications: challenges and directions

Abstract

Internet access was the main service supported in legacy access networks via asynchronous transfer mode (ATM)-based digital subscriber line access multiplexers (DSLAMs) and aggregation networks. The broadband remote access server (BRAS) was the Internet Protocol (IP) edge router, and it provided various services including service routing, Point-to-Point Protocol (PPP) handling, shaping, scheduling, and policy-based controls. This architecture is being increasingly replaced by an Ethernet-based aggregation network with potentially multiple broadband network gateways (BNGs) replacing the single BRAS. The migration to Ethernet-based networks is partly driven by the high bandwidth needs of applications such as video on demand (VoD), IP television (IPTV), and the ability to support these applications at cost-effective points. Other drivers that are emerging to further shape the next generation of access networks are examined in this paper. In particular, we focus closely on emerging video and voice applications and the new challenges and requirements they bring. The set of applications and issues that we consider is by no means comprehensive. They have been selected as they pose some interesting challenges and have significant impact on the access network functionality and architecture. For video traffic, we examine the challenges for providing high video quality, fast response for IPTV channel change, and content distribution. For voice, we examine the challenges of emergency standalone operation. Finally, we examine aspects of quality of service (QoS) management, resource control, and network resiliency mechanisms for these emerging applications. We see that the access network needs to become extremely application aware and dynamic and move beyond the traditional IP layer 2/3 forwarding functions in order to meet these challenges effectively.