Transparent flow migration through splicing for multi-homed vehicular Internet gateways

We propose a technique, called FloMiS, by which a flow can be migrated from one network to another without requiring any changes to the endpoints (Internet-based servers or mobile clients). Our work is motivated by the needs of our vehicular Internet service, calledWiRover, through which we provide WiFi connectivity in public transit vehicles - city buses as well as long distance buses operating in and around Madison, WI - using multi-network gateways. In our vehicular environment, we have observed that each cellular path experiences stalls and failures resulting in outages to network traffic. To provide robust and uninterrupted experience for these flows, we implement the FloMiS mechanism in the gateways alone, through which the gateways re-initiate a request for the contents of the interrupted flow and splice them back to the original flow in a manner that is transparent to the mobile clients. FloMiS is designed to optimize the majority of network traffic, which our analysis (of about 6 million real user flows) indicates that FloMiS is capable migrating a flow in as little as two round trip times for more than 93% of the traffic volume. Clients left to their own mechanisms would typically recover after several minutes of disconnectivity.

我们提出一种名为FloMiS的技术，通过该技术，流可以从一个网络迁移到另一个网络，而无需对端点（基于互联网的服务器或移动客户端）进行任何更改。我们的工作是由我们的车载互联网服务WiRover的需求所推动的，通过该服务，我们使用多网络网关在公共交通车辆——城市公交车以及在威斯康星州麦迪逊及其周边运营的长途客车中提供WiFi连接。在我们的车载环境中，我们观察到每个蜂窝路径都会出现停滞和故障，从而导致网络流量中断。为了给这些流提供可靠且不间断的体验，我们仅在网关中实施FloMiS机制，通过该机制，网关重新发起对中断流内容的请求，并以对移动客户端透明的方式将它们拼接回原始流。FloMiS旨在优化大部分网络流量，我们对大约600万个真实用户流的分析表明，对于超过93%的流量，FloMiS能够在短短两个往返时间内迁移一个流。依靠自身机制的客户端通常在断连几分钟后才能恢复。