Peer to Peer Application for Mobile Ad Hoc Networks

The main advantage of peer-to-peer (P2P) systems versus traditional client/server systems lies in achieving scalability and dependability by decentralized organization. Wireless mesh networks as well as ad hoc extensions of the Internet will be rapidly emerging in the commercial market as access networks, since these wireless multihop networks can perform data transfers both several orders of magnitude faster and cheaper than 3G cellular networks. Due to mobility and limited resources, P2P systems for multihop wireless networks require fundamentally new concepts than the ones known for the wired Internet.

This talk will present presents a novel congestion control algorithm for TCP over multihop IEEE 802.11 wireless networks implementing rate-based scheduling of transmissions within the TCP congestion window. The novel TCP variant is denoted as TCP with Adaptive Pacing (TCP-AP). A comprehensive mesurement study in a testbed shows that TCP-AP achieves up to 83% more goodput than the widely deployed TCP NewReno, provides excellent fairness in almost all scenarios, and is highly responsive to changing traffic conditions. Finally, an outline will be presented on how mobile P2P data sharing, e.g. photos and videos in a social network, can be effectively implemented in wireless multi-hop networks via epidemic data dissemination and TCP-AP. The talk concludes with sketching current research projects funded by DFG and BMBF.