ItswTCM: A new aggregate marker to improve fairness in DiffServ

Recent demand for real time applications has given rise to a need for Quality of Service (QoS) in the Internet. Differentiated Services 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 sharing of excess bandwidth among aggregates. 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 middle network provision level (20% - 70%); we believe this is the region where all well provisioned network will operate. Results also show that our proposed marker is not as sensitive to the number of flows as previous markers. We point out that yellow packets play a significant role in achieving proportional fair sharing of excess bandwidth among aggregates. We conclude that in order to achieve proportional fair sharing of excess bandwidth, it is important to inject the right amount of yellow packets into the network.