In this paper, we study the problem of maintaining fairness for TCP connections in wireless local area networks (WLANs), based upon the IEEE 802.11 standard and operating in DCF mode. Although this mode of operation ensures fair access to the medium at the MAC level, it does not provide fairness among TCP connections. TCP unfairness may result in significant degradation of performance, leading to users perceiving unsatisfactory quality of service. We propose and analyze a solution capable of enabling TCP fairness with minimal additional complexity. The proposed solution is based on utilizing an IP rate-limiter with an adaptive rate control mechanism and does not require modifying existing standards at the MAC or network layers. The solution is fully compatible with existing devices and can be integrated either within the access point or within and external device (e.g., the network gateway). The performance analysis is performed in a real test-bed and proves the feasibility and effectiveness of our mechanism. To allow fellow researchers to reproduce our work we published on the WEB all the implementation code.

In this paper, we study the problem of maintaining fairness for TCP connections in wireless local area networks (WLANs) based upon the IEEE 802.11 standard. Current implementations of 802.11 use the so-called distributed coordination function (DCF), which provides similar medium access priority to all stations. Although this mode of operation ensures fair access to the medium at the MAC level, it does not provide any provisions for ensuring fairness among the TCP connections. TCP unfairness may result in significant degradation of performance leading to users perceiving unsatisfactory quality of service. We propose and analyze two solutions that are capable of enabling TCP fairness with minimal additional complexity. The proposed solutions are based on utilizing a rate-control mechanism in two modes: static or adaptive. They do not require modifying existing standards at the MAC or network layers. Hence, they are fully compatible with existing devices. Our performance analysis results prove the efficaciousness of our proposed solutions in achieving TCP fairness compared to existing approaches. We have, also, implemented the proposed solutions in an ad-hoc experimental test-bed, and performed measurements to demonstrate the validity of our approach and results

This work presents a general layer-2 approach for routing and load balancing in Wireless Infrastructure Mesh Network The key idea is dynamic select routes among a set of slowly changing alternative network paths. Our approach decouples the routing and load balancing problem into two distinct sub-problems: path creation and path selection. Paths are created through the reuse of classical 802.1Q multiple spanning tree mechanisms. This guarantees that, for each formed tree, a path is deployed from each mesh node to the Mesh Gateway. Moreover, each tree (path) is assigned a Virtual LAN identifier. Path selection is driven by a local algorithm running at each mesh node, fed by measurements (taken along each path connecting the mesh node to the gateway) which allow to dynamically determine which are the best paths. In order to route a packet it is sufficient to mark the packet with the VLAN tag corresponding to the chosen path. The described approach provides a very general and flexible framework: performance/stability trade-offs can be tuned through the choice of i) the mechanism used to measure the path quality; ii) the algorithm employed to select the path, and iii) the system parameter used (link costs and link weights) for the multiple spanning tree formation.

Deployment of 802.11 wireless LANs is increasingly on the rise leading to new service scenarios in which users are connected everywhere-everytime. However the IEEE 802.11 standard was designed for short range wireless data transmissions and does not natively provide any support for roaming amongst different access networks. In the more general case, a mobile user should be expected to be able to roam into a visited domain and gain access to the network on the basis of some credentials shared with his home domain or WISP. There are several mechanisms that can be involved in providing such access control and roaming functionality but no any standard has overcome. In this paper a new SIP based solution is proposed. SIP-based authentication is provided end-to-end between user-to-network and network-to-network. The proposed solution realizes full proxy-to-proxy authentication at SIP level, enabling dynamic and secure WISP-to-WISP interworking. The proposed solution has been also implemented and successfully tested in a demonstrating testbed