Licklider Transmission Protocol - Specification
Licklider Transmission Protocol - Specification
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DOI：
10.17487/rfc5326
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发表时间：
2008-09
期刊：
影响因子：
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通讯作者：
M. Ramadas;S. Burleigh;S. Farrell
中科院分区：
文献类型：
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作者：
M. Ramadas;S. Burleigh;S. Farrell
本文档描述了Licklider传输协议（LTP），旨在通过具有超长消息往返时间（RTT）和/或频繁连接中断的链路提供基于重传的可靠性。由于跨行星际空间的通信是这种环境的最突出的例子，LTP主要旨在支持行星际空间中的“长距离”可靠传输，但它也可以应用于其他环境。LTP通过请求选择性确认接收报告来进行数据传输的ARQ。它是有状态的，没有协商或握手。在部署由延迟容忍网络研究组正在开发的捆绑协议的星际互联网设置中，LTP旨在充当在直接RF通信的相邻星际互联网节点之间以成对方式操作的可靠的“汇聚层”协议。在该操作场景中，并且潜在地在捆绑协议的一些其他部署中，LTP直接在数据链路层协议上运行;在这种情况下，底层数据链路层协议中的前向纠错编码和/或校验和机制必须确保在通信实体之间传递的数据的完整性。由于在LTP的设计中没有包括用于流控制或拥塞控制的机制，因此该协议不旨在或不适合于在全球互联网中无处不在的部署。当LTP在UDP上运行时，它只能用于软件开发或专用局域网。当LTP不运行在UDP上时，它必须直接运行在一个协议（名义上是一个链路层协议）上，该协议满足第5节中指定的要求。本文档是延迟容忍网络研究小组的产品，并已由该小组审查。没有人反对将其作为RFC发布。
This document describes the Licklider Transmission Protocol (LTP), designed to provide retransmission-based reliability over links characterized by extremely long message round-trip times (RTTs) and/or frequent interruptions in connectivity. Since communication across interplanetary space is the most prominent example of this sort of environment, LTP is principally aimed at supporting "long- haul" reliable transmission in interplanetary space, but it has applications in other environments as well. LTP does ARQ of data transmissions by soliciting selective- acknowledgment reception reports. It is stateful, and has no negotiation or handshakes. In an Interplanetary Internet setting deploying the Bundle protocol that is being developed by the Delay Tolerant Networking Research Group, LTP is intended to serve as a reliable "convergence layer" protocol operating in pairwise fashion between adjacent Interplanetary Internet nodes that are in direct RF communication. In that operational scenario, and potentially in some other deployments of the Bundle Protocol, LTP runs directly over a data- link layer protocol; when this is the case, forward error correction coding and/or checksum mechanisms in the underlying data- link layer protocol must assure the integrity of the data passed between the communicating entities. Since no mechanisms for flow control or congestion control are included in the design of LTP, this protocol is not intended or appropriate for ubiquitous deployment in the global Internet. When LTP is run over UDP, it must only be used for software development or in private local area networks. When LTP is not run over UDP, it must be run directly over a protocol, (nominally a link- layer protocol), that meets the requirements specified in section 5. This document is a product of the Delay Tolerant Networking Research Group and has been reviewed by that group. No objections to its publication as an RFC were raised.