A Feasibility Study of Mesh Networks for an All-Wireless Office

There is a fair amount of evidence that mesh (static multihop wireless) networks are gaining popularity, both in the academic literature and in the commercial space. Nonetheless, none of the prior work has evaluated the feasibility of applications on mesh through the use of deployed networks and real user traffic. The state of the art is the use of deployed testbeds with synthetic traces consisting of random traffic patterns. In this paper, we evaluate the feasibility of a mesh network for an allwireless office using traces of office users and an actual 21-node multi-radio mesh testbed in an office area. Unlike previous mesh studies that have examined routing design in detail, we examine how different office mesh design choices impact the performance of user traffic. From our traces of 11 users spanning over a month, we identify 3 one hour trace periods with different characteristics and evaluate network performance for them. In addition, we consider different user-server placement, different wireless hardware, different wireless settings and different routing metrics. We find that our captured traffic is significantly different from the synthetic workloads typically used in the prior work. Our trace capture and replay methodology allows us to directly quantify the feasibility of office meshes by measuring the additional delay experienced by individual transactions made by user applications. Performance on our mesh network depends on the routing metric chosen, the user-server placement and the traffic load period. The choice of wireless hardware and wireless settings has a significant impact on performance under heavy load and challenging placement. Ultimately we conclude that for our traces and deployed system, under most conditions, all-wireless office meshes are feasible. In most cases, individual transactions incur under 20ms of additional delay over the mesh network. We believe this is an acceptable delay for most applications where a wired network to every machine is not readily available. We argue that our results are scalable to a network of over 100 users.

有相当多的证据表明，网状（静态多跳无线）网络在学术文献和商业领域都越来越受欢迎。然而，之前的研究工作都没有通过已部署的网络和真实的用户流量来评估网状网络应用的可行性。目前的技术水平是使用带有由随机流量模式组成的合成跟踪数据的已部署测试平台。在本文中，我们使用办公室用户的跟踪数据以及在办公区域实际的21节点多无线电网状测试平台，评估全无线办公室网状网络的可行性。与之前详细研究路由设计的网状网络研究不同，我们研究不同的办公室网状网络设计选择如何影响用户流量的性能。从我们对11个用户跨越一个月的跟踪数据中，我们确定了3个具有不同特征的1小时跟踪时段，并对它们的网络性能进行了评估。此外，我们考虑了不同的用户 - 服务器放置位置、不同的无线硬件、不同的无线设置以及不同的路由度量标准。我们发现我们所捕获的流量与之前研究工作中通常使用的合成工作负载有显著差异。我们的跟踪捕获和重放方法使我们能够通过测量用户应用程序的单个事务所经历的额外延迟，直接量化办公室网状网络的可行性。我们的网状网络的性能取决于所选的路由度量标准、用户 - 服务器放置位置以及流量负载时段。无线硬件和无线设置的选择在高负载和具有挑战性的放置情况下对性能有重大影响。最终我们得出结论，对于我们的跟踪数据和已部署的系统，在大多数情况下，全无线办公室网状网络是可行的。在大多数情况下，单个事务在网状网络上产生的额外延迟低于20毫秒。我们认为，对于大多数无法轻易获得每台机器的有线网络的应用程序来说，这是一个可接受的延迟。我们认为我们的结果可扩展到超过100个用户的网络。