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At the BoF in Dublin, we observed strong interest and consensus that the TANA work should go forward as a working group. Does the following proposed charter, based on the BoF description, capture what the community was interested in? Thanks, -- Stas Techniques for Advanced Networking Applications (TANA) WG Chair(s): TBD Transport Area Director(s): * Magnus Westerlund <magnus.westerlund at ericsson.com> * Lars Eggert <lars.eggert at nokia.com> Transport Area Advisor: * Lars Eggert <lars.eggert at nokia.com> Mailing Lists: General Discussion: tana at ietf.org To Subscribe: tana-request at ietf.org In Body: (un)subscribe Archive: http://www.ietf.org/mail-archive/web/tana/ Description of Working Group: The TANA WG is chartered to standardize a congestion control mechanism that should saturate the bottleneck, maintain low delay, and yield to standard TCP. Applications that transmit large amounts of data for a long time with congestion-limited TCP, but without ECN fill the buffer at the head of the bottleneck link. This increases the delay experienced by other applications. In the best case, with an ideally sized buffer of one RTT, the delay doubles. In some cases, the extra delay may be much larger. This is a particularly acute and common case is when P2P applications upload over thin home uplinks: delays in these cases can sometimes be of the order of seconds. The IETF's standard end-to-end transport protocols have not been designed to minimize the extra delay introduced by them into the network. TCP, as a side effect of filling the buffer until it experiences drop-tail loss, effectively maximizes the delay. While this works well for applications that are not delay-sensitive, it harms interactive applications that share the same bottleneck. VoIP and games are particularly affected, but even web browsing may become problematic. TANA is a transport-area WG that will focus on broadly applicable techniques that allow large amounts of data to be consistently transmitted without substantially affecting the delays experienced by other users and applications. The WG will work on the following: (1) An experimental congestion control algorithm for less-than-best-effort "background" transmissions, i.e., an algorithm that attempts to scavenge otherwise idle bandwidth for its transmissions in a way that minimizes interference with regular best-effort traffic. Desired features of such an algorithm are: * saturate the bottleneck, * eliminate long standing queues and thus keep delay low when no other traffic is present, * quickly yield to regular best-effort traffic that uses standard TCP congestion control, * add little to the queueing delays induced by TCP traffic, * operate well in today's typical networks with FIFO queueing with drop-tail discipline, * where available, use explicit congestion notification (ECN), active queue management (AQM), and/or end-to-end differentiated services (DiffServ). Application of this algorithm to existing transport protocols (TCP, SCTP, DCCP) is expected to occur in the working groups that maintain those protocols. (2) A document that clarifies the current practices of application design and reasons behind them and discusses the tradeoffs surrounding the use of many concurrent transport connections to one peer and/or to different peers. Standard Internet congestion control result in different transport connections sharing bottleneck capacity. When an application uses several unchoked and not rate-limited transport connections to transfer through a bottleneck, it may obtain a larger fraction of the bottleneck than if it had used fewer connections. Although capacity is the most commonly considered bottleneck resource, middlebox state table entries are also an important resource for an end system communication. Other resource types may exist, and the guidelines are expected to comprehensively discuss them. Applications use a variety of techniques to mitigate these concerns. These techniques have not always been reviewed by the IETF and their interaction with TCP dynamics is poorly understood. The WG document the known techniques, discussing the consequences and, where appropriate, provide guidance to application designers. (3) The WG will discuss how to best take into account prior work in the area. The outcome will be either incorporated into the document specifying the experimental congestion control algorithm or into a separate document summarizing prior work. Goals and Milestones TBD Submit "Multiple Transport Connections in Applications Design" to the IESG for consideration as an Informational RFC TBD Submit "Transport for Advanced Networking Applications (TANA)" to the IESG for consideration as an Experimental RFC Internet-Drafts Transport for Advanced Networking Applications (TANA) Problem Statement http://www.ietf.org/internet-drafts/draft-shalunov-tana-problem-statement-01.txt No Requests for Comments |
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