771096
UAMAC: Unidirectional-Link Aware MAC Protocol for Heterogeneous Ad Hoc Networks
In heterogeneous ad hoc networks, high-power nodes could potentially interfere with any on-going transmissions of low-power nodes. In this paper, we propose a unidirectional-link aware MAC protocol (UAMAC) which prevents such an interference problem by reserving the wireless channel of unidirectional high-power node selectively over one-hop. Our preliminary performance results show that the UAMAC works well in these heterogeneous environments with unidirectional links.
28860469
An Efficient Neighbor Knowledge Based Broadcasting for Mobile Ad Hoc Networks
Although a flooding is the most commonly used method for one-to-all communications, it often results in huge traffic in mobile ad hoc networks. Several optimization schemes have been proposed to alleviate this problem. However, none of them offers a complete solution and has their own limitations, such as, lack of reliability, high latency or excessive control packet overhead. In this paper, we propose the FONIAH (Flooding based on One- hop Neighbor Information and Adaptive Holding) scheme to overcome these limitations.
42623736
Impossible Differential Cryptanalysis of Reduced Round XTEA and TEA
We present the impossible differential cryptanalysis of the block cipher XTEA[7] and TEA[6]. The core of the design principle of these block ciphers is an easy implementation and a simplicity. But this simplicity dose not offer a large diffusion property. Our impossible differential cryptanalysis of reduced-round versions of XTEA and TEA is based on this fact. We will show how to construct a 12-round impossible characteristic of XTEA. We can then derive 128-bit user key of the 14- round XTEA with 262.5 chosen plaintexts and 285 encryption times using the 12-round impossible characteristic. In addition, we will show how to construct a 10-round impossible characteristic of TEA. Then we can derive 128-bit user key of the 11-round TEA with 252.5 chosen plaintexts and 284 encryption times using the 10-round impossible characteristic.
11234364
Robust routing in wireless ad hoc networks
A wireless ad hoc network is a collection of mobile nodes with no fixed infrastructure. The absence of a central authorization facility in dynamic and distributed environments requires collaboration among nodes. When a source searches for a route to a destination, an intermediate node can reply with its cached entry. To strengthen correctness of such a routing discovery process, we propose a method in which the intermediate node requests its next hop to send a confirmation message to the source. After receiving both a route reply and confirmation message, the source determines the validity of a path according to its policy. As a result, this strategy discourages malicious nodes from intercepting packets. Simulation results show a remarkable improvement in throughput (30% higher delivery ratio and 10% less data transmission overhead) with a moderate increase of control messages.
36131867
Lambda GLSP setup with QoS requirements in optical Internet
GMPLS is currently being specified as the control plane for next generation optical networks. While one merit of GMPLS is that network operators are able to control the traffic of Internet Protocol (IP) and thus offer performance superior to that of traditional Internet Gateway Protocols (IGP), it has been a challenge to develop an efficient Traffic Engineering (TE) technique to satisfy the different traffic requirements of end-users in GMPLS domain. Several TE techniques have been thought of by creating a set of Generalized Label Switched Paths (GLSPs) in the optical network. In this paper we present a technique for establishing GLSP in optical Internet, that supports Quality of Service (QoS) considering the traffic flows with delay QoS requirements. This approach accounts for the processing delay at the network layer that may be encountered in optical nodes that terminate lightpaths and perform some types of traffic grooming. Additionally, we extend the QoS routing framework by defining additional extensions that can be used in conjunction with Shared Risk Group (SRG) identifiers to reserve backup paths that do not share network resources with the working paths that they are protecting. We provide some simulation results to demonstrate the effectiveness of our routing algorithms.
52861172
Allocation of Signature File on Parallel Device for WWW Index Servers
Signature files are widely used in information retrieval and database. They act as search filters for content-based retrieval. In a large database server, a parallel device is utilized to achieve concurrency access. Efficient allocation of signature files on parallel devices minimizes the query response time and is important in the design of access methods for large scale index servers. We have developed an algorithm to organize the storage of signatures in parallel secondary storage to reduce the query response time. First, signature file is clustered into signature pages. Then, the clustered signature pages are distributed among the disks using the parity check matrix of error correcting code in coding theory. Through the construction of error correcting code, the least frequently simultaneously accessed pages are allocated on the same disk. Performance analysis shows that this algorithm improves the efficiency of access.
13015161
Neighbor supporting ad hoc multicast routing protocol
An ad hoc network is a multi-hop wireless network formed by a collection of mobile nodes without the intervention of fixed infrastructure. Limited bandwidth and a high degree of mobility require that routing protocols for ad hoc networks be robust, simple, and energy-conserving. This paper proposes a new ad hoc multicast routing protocol called Neighbor-Supporting Multicast Protocol (NSMP). NSMP adopts a mesh structure to enhance resilience against mobility. And NSMP utilizes node locality to reduce the overhead of route failure recovery and mesh maintenance. NSMP also attempts to improve route efficiency and reduce data transmissions. Our simulation results show that NSMP delivers packets efficiently while substantially reducing control overhead in various environments.