We stated that there was no real bandwidth penalty for using frame relay instead of PPP to do the job. PPP has a major advantage - simplicity. PPP does nothing but provide a minimal link layer, so there's no multiplexing involved. But frame relay's capabilities also involve additional complexity. For corporate networks, it's not a safe assumption that routing, or even switching, at the IP layer is necessarily the most desirable layer for efficient networking.
Most carriers offer a standard set of service-level agreements with their offerings.
Again, the importance of getting this CIR depends on the application, but for sensitive applications such as SNA and voice, the CIR offers significant advantages. Your answer will depend on your need for QoS, the nature of your traffic and the relative importance to you of switching at Layer 2 rather than Layer 3. Steven Taylor , consultant and broadband packet evangelist, and Joanie Wexler, an independent networking technology editor and writer, team up to bring you this analysis and commentary. Taylor specializes in education and market analysis, and Wexler adds incisive reporting and research. Feedback and additional topic ideas are welcome.