Delivery of Guaranteed Rate Internet Traffic with Very Low Delay Jitter

Abstract

Telerobotic control systems can tolerate a fixed delay in the control loop, but are highly sensitive to delay jitter. Before such systems can be widely deployed over the Internet, packet switching techniques which ensure a high 'Quality of Service' (QoS) and low delay jitter will be required. It is shown that guaranteed-rate traffic flows can be delivered over the Internet backbone with very low delay jitter, provided that each IP router (and the destination playback buffer) have the capacity to buffer a small number of switch cells per flow. An RSVP or DiffServ algorithm must be used to reserve guaranteed bandwidth and buffer space in the IP routers. Each IP router must schedule the guaranteed rate traffic for transmission according to a recently proposed QoS switch scheduling algorithm, which exploits a Recursive Fair Stochastic Matrix Decomposition algorithm. Computer simulations illustrate that very low delay jitters can be achieved.I.

Internet Multicasting of IPTV With Essentially-Zero Delay Jitter

“…The low-jitter GR scheduling algorithm removes much of the cell delay variability associated with the dynamic scheduling algorithms used in existing IP routers, and minimizes the amount of buffering required in the IP routers. Extensive simulations indicate that essentially-zero delay jitter is achievable, as confirmed by theoretical results [42], [43], [45] and other experimental results [46], [47]. The extensive simulations indicate that each IP router typically buffers 2 cells (128 bytes) of video data per output port for the aggregated IPTV flow being multicast, significantly less buffering than current IP routers require.…”

“…In an 8 8 crossbar switch with time slots per frame, the minimum allotment of bandwidth is of the line rate, which reserves one time-slot per frame on a recurring basis. Define a new quantized traffic rate matrix where each traffic rate is expressed as an integer number times the minimum quota of reservable bandwidth: Several of the following definitions will be useful (see [35], [42], [46] for similar definitions).…”

“…Theoretical bounds on the delay and jitter for every flow are presented in [43], [45]. The scheduling of multimedia streams through a chain of 10 IP routers was explored in [46]. Simulations indicate that essentially-zero delay jitter can be achieved in a 100% saturated IP network.…”