AuthorsK. Evensen, D. Kaspar, P. E. Engelstad, A. F. Hansen, C. Griwodz and P. Halvorsen
TitleA Network-Layer Proxy for Bandwidth Aggregation and Reduction of IP Packet Reordering
AfilliationCommunication Systems, Communication Systems
Publication TypeProceedings, refereed
Year of Publication2009
Conference NameThe 34rd Annual IEEE Conference on Local Computer Networks (LCN)
Date PublishedJuly
ISBN Number978-1-4244-4488-5

With today's widespread deployment of wireless technologies, it is often the case that a single communication device can select from a variety of access networks. At the same time, there is an ongoing trend towards integration of multiple network interfaces into end-hosts, such as cell phones with HSDPA, Bluetooth and WLAN. By using multiple Internet connections concurrently, network applications can benefit from aggregated bandwidth and increased fault tolerance. However, the heterogeneity of wireless environments introduce challenges with respect to implementation, deployment, and protocol compatibility. Variable link characteristics cause reordering when sending IP packets of the same flow over multiple paths. This paper introduces a multilink proxy that is able to transparently stripe traffic destined for multihomed clients. Operating on the network layer, the proxy uses path monitoring statistics to adapt to changes in throughput and latency. Experimental results obtained from a proof-of-concept implementation verify that our approach is able to fully aggregate the throughput of heterogeneous downlink streams, even if the path characteristics change over time. In addition, our novel method of equalizing delays by buffering packets on the proxy significantly reduces IP packet reordering and the buffer requirements of clients.

Citation KeySimula.ND.369