Summary: ItswTCM: a new aggregate marker to improve fairness in DiffServ
, Mohammed Atiquzzamanb,*
School of Computing, Armstrong Atlantic State University, Savannah, GA 31419, USA
School of Computer Science, University of Oklahoma, Norman, OK 73019-6151, USA
Received 19 March 2002; revised 23 August 2002; accepted 10 October 2002
Recent demands for real time applications have given rise to a need for Quality of Service (QoS) in the Internet. Differentiated Services
(DiffServ) is one of such efforts currently pursued by IETF. Previous researchers found unfairness in the DiffServ network. To solve the
unfairness problem, we propose a new TSW based three-color marker (ItswTCM ), which achieves proportional fair share of excess
bandwidth among aggregates in a DiffServ network. We have compared the fairness of our proposed ItswTCM marker with srTCM, trTCM,
and tswTCM. Results show that our proposed marker performs better than the other three schemes for low to medium network provision level
(2070%); we believe that all well provisioned network will operate in this region. Results also show that our proposed marker is not as
sensitive to the number of flows in an aggregate as the previous marking schemes. We point out that yellow packets play a significant role in
achieving proportional fair share of excess bandwidth among aggregates. We conclude that in order to achieve proportional fair sharing of
excess bandwidth, it is important to inject right amount of yellow packets into the network.
q 2002 Elsevier Science B.V. All rights reserved.
Keywords: TCP protocol; Quality of service; Differentiated services; Traffic Marker