Abstract: Broadband – Integrated Service Digital Network (B-ISDN) based telecommunication systems support a variety of services. Such as: landline, computer data and video conferencing. This thesis deals with the Quality of Service (QoS) in B-ISDN from the traffic control perspective. The main goal is to allocate bandwidth to network users with bursty traffic characteristics using a dynamic traffic control algorithm called the Bandwidth Contracting Algorithm (BCA). The above algorithm has four types of contracts: Red, Yellow, Short Term Green (STG) and Long Term Green (LTG) contracts. The STG contract is of special interest as its working area targets bursty applications that are sensitive to cell loss but insensitive to cell delay and delay variations. Two types of control mechanisms were simulated to implement the STG contract type: the Immediate Allocation / Explicit Release (IA/ER) and Delayed Allocation / Implicit Release (DA/IR). These two control mechanisms deal with different processing and arrival requirements criterions. The Simulation of BCA using STG contract was carried out based on homogeneous and heterogeneous models. They differ in behavior according to the sources generating traffic pattern and the specific control mechanism imposed in the particular network. Also, the bandwidth aware queue has been used in the heterogeneous network model. The simulation of BCA algorithm was carried out using MATLAB Version 7.6.0.324, (R2008a) edition. As an example, when the number of sources is 60, the blocking probability for the IA/ER is 0.7 and for the DA/IR is 0.3, but when there are 120 sources in the network, the blocking probability is the same for both schemes. When the number of sources is 60, the STG waiting time is 26 ms for the IA/ER and it is 14 ms for DA/IR schemes but as the number of sources increases to reach 120, the waiting time difference increases to be 100 ms for the IA/ER and 50 ms for the DA/IR scheme.