Uma análise dos problemas do protocolo TCP em redes assimétricas e soluções existentes

Abstract

The asymmetric networks have gained wide acceptance in the market for Internet access because of its ease of implementation, which requires only one phone line for this. The architecture of these networks was made considering that the User is more passive than active when interacting with the Web, that is, it download more than upload from hiscomputer. With the emergence of Web 2.0 and P2P networks, new paradigms have emerged significantly changing the behavior of User, which is now so active as passive in traffic information for the Internet. The TCP (Transmission Control Protocol) is a protocol of transport layer of the TCP / IP and is now the most widely used in Internet applications. TCP has some important characteristics as the reliability in the deliveryof segments sent, using confirmations to the packet that arrives correctly (the ACKs). This packets are used to see if the network is congested or not, to regulate amount of data that will be sent by the sender of the transmission. When TCP is placed in asymmetric networks, with data segments being transmitted in both directions, we have the return channel for ACKs (uplink) will not be enough to send all the dataand ACKs at the same time, creating delays for ACKs. This will cause delays or even losses in some situations, and therefore will reduce the performance of TCP. This paper aims to study this problem, raising the causes, modeling it mathematically to better understanding and studying other problems that seek to solve it, categorizing them according to their approach, which may be changing the TCP or other devicesincluding the entrances of the channels to perform the tasks.