ATM virtual private networks

Abstract

Asynchronous transfer mode (ATM) networks are aimed at supporting a variety of services, including voice, video and data, while allowing the users to efficiently share network resources. Efficiency and flexibility in managing the resources are essential to meet the different quality requirements of these services. Network resources include trunk bandwidth, switching capacity, and buffer space in the ATM cross-connects. Sharing these resources is a complex task, since different applications have different traffic characteristic and quality of service (QOS) requirements. For example, video is characterized by continuous bit rate (CBR) or variable bit rate (VBR) traffic, while voice and data are bursty in nature. The quality requirements also depend on the type of service under considerations—some services, like video and voice, have strict end-to-end delay requirements, whereas others may be carried on a best-effort basis.