ted broadband services such as DSL and cable modems may signal the end of Frame Relay's popularity. Nonetheless, there are still locations, such as rural areas, where DSL and cable modems are not available, and in those cases the Frame Relay alternative still presents the least costly approach to an always-on connection, allowing an enterprise with rural branches to connect those offices to the corporate WAN. ATM is a series of standards that the ITU-T introduced in 1988 as part of a larger vision for the future of networks called Broadband ISDN. Broadband ISDN defined new genre of applications, and most of those applications, not surprisingly, involved video or multimedia content, and this is where ATM shines. ATM was designed to be a master integrator: one platform, one infrastructure over which voice, data, video, multimedia, images, and other forms of traffic that we may have not thought of yet can all coexist and all be assigned the appropriate network resources based on their needs. ATM wasn't designed to be a technique for voice; it wasn't designed as a new solution for data. It was designed for multimedia, but it hasn't yet had a chance to really demonstrate its greatest strengths in today's environment. A huge number of networks-roughly 80% to 85% of all Internet backbones and Frame Relay networks-have ATM at their core. Today, ATM is still the only WAN approach that provides an architected QoS, which then gives network operators the opportunity to manage the traffic inside the network, which is a prerequisite to being Chapter 7 Wide Area Networking able to offer business-class services, such as VPNs, VoFR, Voice over IP (VoIP), and Voice over ATM (VoATM). (However, it is important to note that today, MPLS, com- bined with RSVP-TE or CR-LDP, provides vastly improved QoS capabilities to the IP world, approaching that of ATM's structured architecture.) ATM has the capability to provide the appropriate guarantees to delay-sensitive traffic. ATM is working on your behalf more than may be evident in what you 