Three-way Handshake Research Articles

Distributed scheduling based on polling policy with maximal spatial reuse in multi-hop WMNs

The scheduling algorithm based on the three-way handshaking scheme in IEEE 802.16d-2004 standard has some serious problems because of the complexity of the algorithm and low scheduling efficiency. To enhance the scheduling efficiency and improve the performance of multi-hop wireless mesh networks (WMNs), one distributed scheduling algorithm that can maximize the spatial and time reuse with an interference-based network model is proposed. Compared to the graph-based network model, the proposed network model can achieve a better throughput performance with maximal spatial reuse. Furthermore, this proposed scheduling algorithm also keeps fairly scheduling to all links, with a priority-based polling policy. Both the theoretical analysis and simulation results show that this proposed distributed scheduling algorithm is simple and efficient.

On-the-fly TCP path selection algorithm in access link load balancing

Many enterprises install multiple access links for fault tolerance or bandwidth enlargement. Dispatching connections through good links is the ultimate goal in utilizing multiple access links. The traditional dispatching method is only based on the condition of the access links to ISPs. It may achieve fair utilization on the access links but poor performance on connection throughput. In this work, we propose a novel approach to maximize the per-connection end-to-end throughput by the on-the-fly round trip time (RTT) probing mechanism. The end-to-end RTTs through all possible links are probed by duplicating the SYN packet during the three-way handshaking stage of a TCP connection. The experiment results show that the ratio to choose the best outgoing access link is 79% on the average. If the second best link is chosen, it is usually very close to the best, thus averagely achieving 94% of the maximum possible throughput. The ratio of the traditional round-robin (RR) algorithm is only 35%, and the link selected by RR algorithm could provide 69% of throughput.

Floor acquisition multiple access (FAMA) in single-channel wireless networks

The FAMA-NCS protocol is introduced for wireless LANs and ad-hoc networks that are based on a single channel and asynchronous transmissions (i.e., no time slotting). FAMA-NCS (for floor acquisition multiple access with non-persistent carrier sensing) guarantees that a single sender is able to send data packets free of collisions to a given receiver at any given time. FAMA-NCS is based on a three-way handshake between sender and receiver in which the sender uses non-persistent carrier sensing to transmit a request-to-send (RTS) and the receiver sends a clear-to-send (CTS) that lasts much longer than the RTS to serve as a “busy tone” that forces all hidden nodes to back off long enough to allow a collision-free data packet to arrive at the receiver. It is shown that carrier sensing is needed to support collision-free transmissions in the presence of hidden terminals when nodes transmit RTSs asynchronously. The throughput of FAMA-NCS is analyzed for single-channel networks with and without hidden terminals; the analysis shows that FAMA-NCS performs better than ALOHA, CSMA, and all prior proposals based on collision avoidance dialogues (e.g., MACA, MACAW, and IEEE 802.11 DFWMAC) in the presence of hidden terminals. Simulation experiments are used to confirm the analytical results.

The level of handshake required for managing a connection

A connection between two hosts across a wide-area network may consist of many sessions over time, each called an incarnation. A connection is synchronized using a connection establishment protocol, based on a handshake mechanism, to allow reliable exchange of data. This paper identifies the precise level of handshake needed under different assumptions on the nodes and on the network, using a formal model for connection management. In particular, the following parameters are studied: the size of the memory at the nodes, the information retained between incarnations, and the existence of time constraints on the network. Among the results we obtain are: (1) If both nodes have bounded memory, no incarnation management protocol exists. (2) If the nodes have unbounded memory, then a two-way handshake incarnation management protocol exists. (3) If the nodes have unbounded memory, and the server does not retain connection-specific information between incarnations, then a three-way handshake incarnation management protocol exists. On the other hand, a two-way handshake incarnation management protocol does not exist, even if some global information is retained. (4) If a bound on maximum packet lifetime (MPL) is known, then a two-way handshake incarnation management protocol exists, in which the server does not retain connection-specific information between incarnations.