Date Added: Aug 2011
ISPs are increasingly offering a variety of network-based services such as VPN, VPLS, VoIP, Virtual-Wire and DDoS protection. Although both enterprise and residential networks are rapidly adopting these services, there is little systematic work on the design challenges and trade-offs ISPs face in providing them. The goal of the authors' paper is to understand the complexity underlying the layer-3 design of services and to highlight potential factors that hinder their introduction, evolution and management. Using daily snapshots of configuration and device metadata collected from a tier-1 ISP, they examine the logical dependencies and special cases in device configurations for five different network-based services.