www.tjprc.org editor@tjprc.org THROUGHPUT ANALYSIS OF TCP NEWRENO FOR MULTIPLE BOTTLENECKS MOHIBUR RAHMAN 1 , LUTFUN NAHAR 2 , ZINNIA SULTANA 3 & RASHEDUL ISLAM 4 1 Department of Computer Science & Engineering, University of Chittagong, Bangladesh 2,4 Lecturer, Department of Computer Science & Engineering, International Islamic University Chittagong, Bangladesh 3 Associate Professor, Department of Computer Science & Engineering, International Islamic University Chittagong, Bangladesh ABSTRACT A very complex problem in the network is –congestion control. It is one of the major problems among top listed network problems. A lot of important data might be àt loss, as a result, resources become wasted. Many TCP models have proposed to protect the loss during data transfer. They differ from each other on the basis of algorithm for congestion control and segment loss recovery technique. TCP NewReno is one of them that we have proposed in our paper, and it is also an analytical model for the throughput of TCP NewReno. This performance is given for multiple bottlenecks -a queue management mechanism. In our paper, we show that increased throughput of TCP New Reno over Reno and how NewReno suffers from less packet loss rate than the Reno model, by using the NS-2 simulator. KEYWORDS: TCP, Reno, UDP & NewReno Received: Jan 02, 2017; Accepted: Jan 24, 2017; Published: Jun 03, 2017; Paper Id.: IJCNWMCJUN20172 INTRODUCTION There are two unique transport-layer protocols, one is User Datagram Protocol (UDP) and the other is Transmission Control Protocol (TCP). An unreliable and connectionless protocol is UDP, where TCP is a connection-oriented, reliable protocol. In case of TCP, a connection must be established before any data, when the data transferred between two processes, a connection must be established before data transfer. IT gives reliable data transfer by using sequence numbers, flow control, timers, and acknowledgements. It guarantees that data is transferred from the sender to the receiver, correctly and in-sequence. r. It gives full-duplex, one way data transfer in the Internet. To prevent loss, it provides various mechanisms. Congestion control is one of them, that prevents a router from overflowing. Literature Review TCP, the congestion control mechanism is used to protect the network from overflowing of data packets. TCP uses end-to-end congestion control mechanism, since the IP layer provides no explicit feedback to the end systems regarding network congestions. It dynamically resizes the congestion window, depending on the behavior of the network- packet loss, delay, etc. It increases the congestion window size when there is available bandwidth and decreases the window when there is congestion. The TCP congestion control mechanism, at each side of a connection keep track of a variable, the congestion window (cwnd). It imposes the following constraint on the sending rate: LastByteSent - LastByteACKed≤ min (cwnd, rwnd) this indicates that, the amount of Original Article International Journal of Computer Networking, Wireless and Mobile Communications (IJCNWMC) ISSN (P): 2250-1568; ISSN (E): 2278-9448 Vol. 7, Issue 2, Jun 2017, 19-28 © TJPRC Pvt. Ltd.