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Since its development for WLAN, IE E E 802.11 standard has been widely used for various wireless networks due to the low cost and effectiveness in reducing collisions with simple and decentralized mechanisms. In this paper we present a novel analytical SRN model for performance evaluation of IE E E 802.11 D C F MAC protocol in multi-hop ad hoc networks in the presence of hidden nodes, taking into account the characteristics of the physical layer, different traffic loads, packet size, and carrier sense range. The proposed model captures most features of the protocol. Performance measures such as throughput and packet service time for various network configurations are computed. The proposed models are validated through extensive simulations.

SummaryAddress Resolution Protocol (ARP) is an essential protocol for the operation of local area networks. It is used for mapping the logical address to the physical address. However, ARP was designed without any security features. Therefore, ARP is vulnerable to many ARP spoofing attacks, such as the host impersonation, man-in-the-middle (MITM), and denial of service (DoS) attacks. Many techniques were introduced in the literature for mitigating ARP spoofing attack. However, they could not provide protection against the host impersonation and DoS attacks. This work introduces a new technique to secure address resolution protocol called ARP Authentication (ARP-A). The proposed technique provides authentication for ARP messages and entities. In addition, it converts ARP from a stateless to a stateful protocol. To evaluate the performance of ARP-A, it was implemented on Linux. To investigate the scalability of ARP-A, a new analytical model was designed for it using stochastic reward nets. The results show that, compared with other related schemes introduced in the literature, ARP-A is more efficient in terms of security and performance. ARP is a stateless protocol 2 because it does not store the state of the ARP requests. It processes an ARP Reply message whether or not it sent an ARP Request. Due to its stateless property and lack of integrity and authenticity, ARP has some serious inherent security vulnerabilities. The ARP spoofing attack 3 can be performed by transmitting a spoofed ARP Request or Reply in the network. In this attack, the attacker associates his MAC address with the IP address of the victim. So, the traffic destined to the IP address of the victim will instead be forwarded to the attacker. The ARP spoofing attack is a serious security problem that threats LANs. 4 It is usually used to perform other types of LAN attacks, such as the man-in-the-middle (MITM), 5 denial of service (DoS), 6 and host impersonation attacks. 4