ITR/SI - A Networking Protocol for Underwater Acoustic Networks

我们提出了一个网络层协议的发展，必要的，以增加在浅水环境中的声学通信的效用。越来越多的注意力放在从难以进入的沿海沃茨收集数据，用于各种活动，包括科学研究、工业和商业问题以及军事应用。活动的优势集中在开发可靠的方法，通过困难的时变浅水介质传输收集的信息。然而，目前的网络层协议，这是负责确定流量路由，不提供保证服务质量。目前的协议也可能导致不必要的消息延迟。在声学网络中，由于声音在水中的速度而导致的过度传播延迟，使流量的传递变得复杂。这种传播速度的效果是使通过短跳连接的声学网络的性能与相邻节点之间的链路超过100，000公里的有线网络相似。然而，潜在的好处和增加的potentialfor应用程序的发展，源于无线水下网络的实施，使itworth探索减轻传播延迟的影响的方法。网络流量的路由确定问题的核心是发现网络拓扑，从网络节点提取下一跳的信息，基于流量forwardingdecisions。两种主要方法用于发现路由信息。主动路由方法在网络流量产生之前预先计算路由数据，因此当网络应用程序提交流量时，已经知道适当的路由。反应式路由根据流量提交确定路由信息。这种方法被称为按需路由，它通过只确定支持实际流量模式所需的路由来最大限度地减少路由发现流量，并缓存这些路由信息，以提高对提交流量的响应能力和对拓扑变化的适应能力。这两种方法都有自己的优点，但是，都没有充分支持resourceallocations必要，以确保服务质量的保证水平，我们提出了一种新的网络协议，提供了许多好处的主动路由yetretains反应式协议的适应性。我们的协议是基于一个中央主节点，它定期探测网络的积极参与者节点。在响应探测时，节点向主节点提供足够的信息，以便主节点确定通过网络的所有可能的数据路径。根据这些信息，主节点为网络做出所有的路由决定，并向每个非主节点提供下一次信息，从而减少了非主节点的工作量。这些信息还使主节点能够优化网络路径的流量分配，提供对延迟的主动管理，确保延迟方差和数据容量在既定的服务质量承诺范围内，这种方法的基础是控制流量与数据传输的分离.这种分离允许数据传输，而不必首先等待传统的握手机制来提供对信道的访问。网络层协议的发展将扩大水声网络的应用范围，使其不仅仅局限于数据速率非常低的通信和非时间敏感的数据类型。这项研究活动的具体受益者包括可部署的自主分布式系统、海洋网技术演示、自主海洋学采样网络和国家海洋学合作伙伴计划前沿解析观测网络与遥感项目。

We propose development of a network layer protocol necessary to increase the utility of acousticcommunications in the shallow water environment. Increasing attention has been given to collecting datafrom difficult to access coastal waters for diverse activities, to include scientific research, industrial andcommercial concerns, and military applications. The preponderance of activity has focused ondeveloping reliable methods for transmitting the information collected through the difficult time-varyingshallow water medium. However, current network layer protocols, which are responsible for determiningtraffic routing, do not provide for guaranteed quality of services. Current protocols also may causeunnecessary message delays.The delivery of traffic in an acoustic network is complicated by the excessive propagation delaysresulting from the speed of sound in water. The effect of this propagation speed is to cause an acousticnetwork connected by short hops to perform similar to a wire-based network with links betweenneighboring nodes of over 100,000 kilometers. However, the potential benefits and increased potentialfor application developments that stem from the implementation of wireless underwater networks make itworthwhile to explore means of mitigating the effects of the propagation delays.Central to the problem of route determination for network traffic is the discovery of the networkstopology from which network nodes extract next-hop information upon which to base traffic forwardingdecisions. Two principal methods are used for discovering the route information. Proactive routingmethods pre-compute route data before network traffic is generated, thus when traffic is submitted bynetwork applications the appropriate routes are already known. Reactive routing determines the routeinformation in response to traffic submissions. This method, referred to as on-demand routing, seeks tominimize route discovery traffic by only determining routes necessary to support actual traffic patterns.This routing information is cached to increase responsiveness to submitted traffic and adaptability totopology changes. Both methods have their merits; however, neither adequately supports resourceallocations necessary to assure guaranteed levels of service quality.We proposed a novel network protocol that provides many of the benefits of proactive routing yetretains the adaptability of reactive protocols. Our protocol is based upon a central master node whichperiodically probes the network for active participant nodes. In responding to the probes, the nodesprovide the master node with sufficient information for the master node to determine all possible datapaths through the network. From this information the master node makes all routing decisions for thenetwork and provides irnext-hoply information to each non-master node, thus reducing the workload onnon-master nodes. This information also enables the master node to optimize the allocation of traffic tonetwork paths providing for active management of delays insuring delay variance and data capacity arewithin the established quality of service commitments.Fundamental to this approach is the separation of control traffic from data delivery. This separationallows data to be transmitted without first having to wait for traditional handshake mechanisms to provideaccess to the channel. This separation significantly reduces the expected delay to which traffic issubjected resulting in potentially higher data throughput.Progress in network layer protocols will expand the usefulness of underwater acoustic networksbeyond applications that are limited to very low data rate traffic and non-time sensitive data types.Specific beneficiaries of this research activity include the Deployable Autonomous Distributed System,the SeaWeb Technology Demonstrations, the Autonomous Oceanographic Sampling Network, and theNational Oceanographic partnership Programs Front Resolving Observational Network with Telemetry(FRONT) project.