http://blogs.najah.edu/author/haya-sammaneh An-Najah Blogs :: Haya Yasser Hassan Sammaneh en-us Sat, 27 Jul 2024 14:20:50 IDT Sat, 27 Jul 2024 14:20:50 IDT [email protected] [email protected] http://blogs.najah.edu/staff/haya-sammaneh/article/An-analytical-Model-for-ShortLiveddocPublished ArticlesThe transmission control protocol TCP is widely used in wired and wireless networks It provides reliable transport services between end-to-end hosts Since TCP performance affects the overall network performance several analytical models were proposed to describe the steady-state throughput of bulk transfer TCP flows ie a flow with large amount of data to send such as FTP transfers However most TCP flows in the Internet world are short-lived to see few losses and they cannot reach the steady-state consequently their performance is determined by the startup effects such as the connection establishment and the slow start mechanisms Surprisingly all of the previous models did not investigate the heterogeneity of wireless networks The heterogeneity is shown by different characteristics and different segment loss probability for various types of wireless networks such as IEEE 80211 WLAN and 3G cellular network Moreover wireless TCP flows are much shorter than wired flows due to the time varying characteristics of wireless networks In this research a recursive and analytical model is developed and used to determine the performance of TCP in heterogeneous wired-cum-wireless networks in terms of average completion time for the short-lived TCP flows is proposed The proposed model focuses on heterogeneous wireless networks The model tackles two different schemes namely End-to-End scheme that solve the wireless loss problems by the end hosts and Connection Division scheme that split the connection at base station aiming to distinguish different characteristics between different networks The proposed model is based on the knowledge of average dropping probability the average round trip time and the flow size in both wired and wireless links The analytical model has been validated by means of simulations and using NS-2 simulator The performance metric of TCP is the average completion time which is the time that the source takes to successfully transfer a given amount of data in addition to the connection establishment time It is shown clearly that the proposed model reflects the behavior of TCP; especially in computing the average completion time that increases as the session size ie the number of data segments in the flow increases The simulation results are very much the same as the values obtained from the analytical model The percentage difference for the average completion time in Sec is less than 3 and 6 for the End-to-End scheme and the Connection Division scheme respectively The model can be used by engineers to tune some of parameters to see its effect on the behaviour of TCP