Skip to Main Content
IP service, leased-line service and POTS service have been the three long-standing communication service offerings of providers. Recently, both commercial and research-and-education network providers have started offering optical dynamic circuit services. This article reviews these services, differentiates DCS from leased-line services, offers a classification of DCS, and proposes two new types of DCS. DCS are classified into two types: Specified-Duration Scheduled and Unspecified-Duration Unscheduled. SDS service is less flexible than UDU service in that it requires users to specify call durations, and is more complex (needs reservation schedulers), but it is the only efficient option if link bandwidth is divided into a small number of channels (e.g., 1 Gb/s circuits on a 10 Gb/s link for fast transfers of large files). For SDS offerings, if the mean call duration is small, then a distributed scheduler implementation may be required to handle the high call arrival load required to maintain high utilization levels. Finally, SDS is classified into two sub-types: Specified Start Time and Earliest Start Time, based on whether the user can only accept a start time from within its own specified set of start times, or whether it can accept any, preferably earliest, start time. The SST sub-type is useful for applications requiring the co-scheduling of network bandwidth with other resources, while the EST sub-type is ideal for file transfers.