Performance Evaluation of Prioritized Buffer Management in Asynchronous and Synchronous Optical Routers

Abstract

The explosive growth of the internet demands more and more bandwidth, in particular for the core network. The rapid advance of wavelength division multiplexing (WDM) technology provides to exploit the huge capacity of optical fiber. According to the present day requirements encourag to study internet traffic supporting with quality of service (QoS). Since the future integrated internet will require differentiated services, where applications such as video conferencing and distance learning will demand a higher QoS than file transfer or web browsing. Wavelength converters improve network blocking performance as well as QoS management. Efficient buffer management schemes for QoS are necessary to minimize probability of packet loss (PPL). The introduction of space priorities is an efficient buffer management scheme in which the buffers are controlled by a threshold. In this thesis, the study in terms of PPL comparing the two conventional buffer management strategies, introducing a threshold in primary buffer (PB) and recirculation buffer (RB) of feedback (FB) type WDM optical routers are presented. We compare the switching performance between the two partial buffer sharing (PBS) strategies. Through the simulation, it is found that the PBS strategy in PB is not an efficient scheme for both asynchronous and synchronous WDM optical routers. The PBS strategy in PB leads to a new scheme by reducing the number of re-circulations for low priority (lp) packets, which is named as constrained threshold in PB (CTPB). PBS in RB shows good performance compared to PBS in PB strategy but the new strategy CTPB dominates the two conventional strategies in attaining differentiated services.