Service Comparison
Engineer Network for Peak Traffic Needs
CSU/DSU per Leased Line per
Time Division Multiplexing
Resiliency is Not Inherent
Engineer Network for Average Traffic Needs
CSU/DSU per Leased Line that can access many remote sites
Statistical Multiplexing and Burst Capability
Resiliency is Inherent in Network
Notes:
• Private lines use time division multiplexing where fixed time slots or channels are dedicated to specific applications whether the applications are active or not. Private lines are generally designed to meet peak traffic delivery objectives. This translates into excess bandwidth or idle capacity during non-peak hours. Private lines are more susceptible to network downtime because the network does not automatically reroute around physical network failures such as cable cuts, unless the end user invests in intelligent network switches and geographically diverse facilities for backup purposes.
• Statistical multiplexing with frame relay allows applications to share network bandwidth. Network bandwidth is used by active applications only. An active application can have full access to the port connection for the entire duration of time when other applications that share that port are not transmitting or receiving. Frame relay can automatically reroute around network failures because the frame relay switches have the intelligence and capability to obtain network status, interpret the status, and take the appropriate action depending on the interpretation, like redirecting traffic to a different trunk because the primary trunk has failed.