More and more satellites are deployed in the space to perform more applications for the benefit of mankind. The future of space technology aims at satellites that can transmit its research data and images from any part of the world, satellites can give high speed internet connection and provide mobile cellular services to people at any place and anytime. It has been simulated and discussed that ISOWC can provide inter-satellite communication at higher speed and much longer distances compared to RF links. Several papers and records have highlighted the advantages of using optical link in place of RF link for inter-satellite communication network but nothing has been studied in depth on the topic. QoS (System Quality of Service) of the system is an important element to really prove that the optical link is superior and more favored over RF links.