Wireless mesh networks (WMNs) have emerged as a promising technology that provides low-cost broadband access to the Internet for fixed and mobile wireless end users. An orthogonal evolution in computer networking has been the rise of peer-to-peer (P2P) applications such as P2P data sharing. It is of interest to enable effective P2P data sharing in this type of networks. Conventional P2P data sharing systems are not cognizant of the underlying network topology and therefore suffer from inefficiency. We argue for dual-layer mesh network architecture with support from wireless mesh routers for P2P applications. The main contribution of this paper is P2PMesh: a topology-aware system that provides combined architecture and efficient schemes for enabling efficient P2P data sharing in WMNs. The P2PMesh architecture utilizes three schemes: (i) an efficient content lookup that mitigates traffic load imbalance at mesh routers; (ii) an efficient establishment of download paths; and (iii) a data transfer protocol for multi-hop wireless networks with limited capacity. We note here that the path establishment and data transfer schemes are specific to P2P traffic and that other traffic would use routes determined by the default routing protocol in the WMN. Simulation results suggest that P2PMesh has the potential to improve the performance of P2P applications in a wireless multi-hop setting; specifically, we focused on data sharing, but other P2P applications can also be supported by this approach. Figure 1. Wireless mesh network architecture.we project forward and expect P2P data sharing traffic to consume a significant amount of the capacity of WMNs.Structured P2P resource sharing systems typically rely on the maintenance of virtual topology on top of the physical network topology and rely on distributed hash tables (DHTs) for locating content in the overlay network (e.g., Chord [6]). This lookup facility acts as a foundation for implementing many P2P resource sharing services such as P2P data sharing. The schemes used in conventional P2P resource sharing systems are application driven, with the objective to improve the performance of the system. However, these schemes are not cognizant of the physical network topology, and there is no consideration of the negative impacts on the underlying network. Therefore, traditional P2P resource sharing systems are inefficient on a WMN where topology information is valuable.We define the underlying network topology awareness, in the context of P2P communications, as the usage of information collected from the underlying physical network to enhance various performance aspects of P2P communications and mitigate negative impacts of P2P communications on the underlying network.Traffic load imbalance is a major cause of performance degradation in WMNs [7]. Most of the network routing protocols in WMNs (e.g., dynamic source routing (DSR) and ad hoc on-demand distance vector (AODV) [8]) use the minimum-hop (shortest path) routing metric [9]. When the network routing protocol uses the minimum-h...