S. Radhakrishnan et al., A FLEXIBLE TRAFFIC SHAPER FOR HIGH-SPEED NETWORKS - DESIGN AND COMPARATIVE-STUDY WITH LEAKY BUCKET, Computer networks and ISDN systems, 28(4), 1996, pp. 453-469
Citations number
19
Categorie Soggetti
Computer Sciences","System Science",Telecommunications,"Engineering, Eletrical & Electronic","Computer Science Information Systems
Maximizing bandwidth utilization and providing performance guarantees,
in the context of multimedia networking, are two incompatible goals.
Heterogeneity of the multimedia sources calls for effective traffic co
ntrol schemes to satisfy their diverse Quality of Service (QoS) requir
ements. These include admission control at connection set up, traffic
control at the source ends and efficient scheduling schemes at the swi
tches. The emphasis in this paper is on traffic control at the source
end. Most multimedia sources are bursty in nature. Traffic shapers hav
e been mainly studied hitherto from the point of view of their effecti
veness in smoothing the burstiness. The Leaky Bucket (LB) scheme, to c
ite an example, is a mean rate policer smoothing at the token generati
on rate. Studies on bursty sources show that burstiness promotes stati
stical multiplexing at the cost of possible congestion. Smoothing, on
the other hand, helps in providing guarantees at the cost of utilizati
on. Thus need for a flexible scheme which can provide a reasonable com
promise between utilization and performance is imminent. Recent studie
s have also questioned the suitability of LB for policing real-time tr
affic due to the excessive delays. We argue for a policy which is less
stringent on short term burstiness than the LB. We propose a new traf
fic shaper which can adjust the burstiness of the input traffic to obt
ain reasonable bandwidth utilization while maintaining statistical ser
vice guarantees. The performance study is conducted in two parts. In t
he first part, we study the effect of varying the shaper parameters on
the input characteristics. In the second part, we dimension our schem
e and a LB equivalently and compare the mean and peak rate policing be
havior with delay and loss as the performance parameters. Adopting a l
ess stringent attitude towards short term burstiness is shown to resul
t in considerable advantage while policing real-time traffic. Future r
esearch possibilities in this topic are explored.