TCP Performance over Gigabit-Capable Passive Optical Networks

The deployment of optical access networks is considered by many as the sole solution able to cope with the ever-increasing bandwidth needs of data and media applications. Gigabit-capable Passive Optical Networks (GPON) are being adopted by many operators worldwide as their preferred fiber-to-the-home network architecture. In such systems, the Medium Access Control (MAC) layer is a key aspect of their operation and performance. TCP is the transport protocol of choice of most popular applications. However, TCP performance is known to be sensitive to the behavior of MAC-layer mechanisms. Thus, it is important to assess the impact that the GPON MAC layer may have on TCP. Motivated by this, in this paper we present a preliminary study of TCP performance issues that may arise in GPON networks. Based on a simple system model, the interaction of some GPON MAC features with TCP is explored both analytically and by simulation.