Networking Choices

Bandwidth You get a lot more bandwidth for the buck with DSL and cable modem services than you do with a traditional frame relay service. However, the Internet services lack the inherent reliability and security of frame relay virtual circuits. If you compare throughput of a typical asymmetric DSL Internet service with standard 56K bit/sec (called DS0) frame relay service in a typical interstate environment, for example, the ADSL service will provide significantly higher throughput in almost all cases for a much lower price. But what if you require service-level guarantees? Is it important for your connection to be up all the time? When there is an outage, is it important that it be corrected and back in service within a specified time period?

Class of Service ISPs are starting to offer business-class ADSL and SDSL services with associated service-level agreements (SLA). As you might expect, these services tend to be more expensive than the common $40 to $60 per month prices which promise “best effort” service. This consumer level service presumes that the connection is non-critical. Business-class DSL offerings are still significantly less expensive than equivalent frame relay services. Further, as a part of the business-class ADSL service, the customer may get fixed IP addresses with domain name service, enabling them to run on-site e-mail and Web services. At higher speeds, the pricing differential between guaranteed IP-over-DSL services and Frame Relay becomes even more pronounced. There remain many outstanding questions: How widely available are these services? How reliable are the guarantees? Are there network metric guarantees other than bandwidth and uptime such as latency and packet loss? But the services deserve comparison, especially for this price differential.