Promoting the use of reliable rate based transport protocols: the Chameleon protocol

Rate-based congestion control, such as TFRC, has not been designed to enable reliability. Indeed, the birth of TFRC protocol has resulted from the need for a congestion-controlled transport protocol in order to carry multimedia traffic. However, certain applications still prefer the use of UDP in order to implement their own congestion control on top of it. The present contribution proposes to design and validate a reliable rate-based protocol based on the combined use of TFRC, SACK and an adapted flow control. We argue that rate-based congestion control is a perfect alternative to window-based congestion control as most of today applications need to interact with the transport layer and should not be only limited to unreliable services. In this paper, we detail the implementation of a reliable rate-based protocol named Chameleon and bring out to the networking community an ns-2 implementation for evaluation purpose

Evaluation of the Impact of Packet Drops due to AQM over Capacity Limited Paths

Postprin

A Network Congestion control Protocol (NCP)

The transmission control protocol (TCP) which is the dominant congestion control protocol at the transport layer is proved to have many performance problems with the growth of the Internet. TCP for instance results in throughput degradation for high bandwidth delay product networks and is unfair for flows with high round trip delays. There have been many patches and modifications to TCP all of which inherit the problems of TCP in spite of some performance improve- ments. On the other hand there are clean-slate design approaches of the Internet. The eXplicit Congestion control Protocol (XCP) and the Rate Control Protocol (RCP) are the prominent clean slate congestion control protocols. Nonetheless, the XCP protocol is also proved to have its own performance problems some of which are its unfairness to long flows (flows with high round trip delay), and many per-packet computations at the router. As shown in this paper RCP also makes gross approximation to its important component that it may only give the performance reports shown in the literature for specific choices of its parameter values and traffic patterns. In this paper we present a new congestion control protocol called Network congestion Control Protocol (NCP). We show that NCP can outperform both TCP, XCP and RCP in terms of among other things fairness and file download times.unpublishe

Mitigating the impact of packet reordering to maximize performance of multimedia applications

We propose a solution to mitigate the performance degradation and corresponding Quality of Experience (QoE) reduction caused by packet reordering for multimedia applications which utilise unreliable transport protocols like the Datagram Congestion Control Protocol (DCCP). We analytically derive the optimum buffer size based on the applications data rate and the maximum delay tolerated by the multimedia application. We propose a dynamically adjustable buffer in the transport protocol receiver which uses this optimum buffer size. We demonstrate, via simulation results, that our solution reduces the packet loss rate, increases the perceived bandwidth and does not increase jitter in the received applications packets while still being within the application's delay limits, therefore resulting in an increased QoE of multimedia applications

Reflections on security options for the real-time transport protocol framework

The Real-time Transport Protocol (RTP) supports a range of video conferencing, telephony, and streaming video ap- plications, but offers few native security features. We discuss the problem of securing RTP, considering the range of applications. We outline why this makes RTP a difficult protocol to secure, and describe the approach we have recently proposed in the IETF to provide security for RTP applications. This approach treats RTP as a framework with a set of extensible security building blocks, and prescribes mandatory-to-implement security at the level of different application classes, rather than at the level of the media transport protocol