AODVSEC: A Novel Approach to Secure Ad Hoc on-Demand Distance Vector (AODV) Routing Protocol from Insider Attacks in MANETs

Mobile Ad hoc Network (MANET) is a collection of mobile nodes that can communicate with each other using multihop wireless links without requiring any fixed based-station infrastructure and centralized management. Each node in the network acts as both a host and a router. In such scenario, designing of an efficient, reliable and secure routing protocol has been a major challenging issue over the last many years. Numerous schemes have been proposed for secure routing protocols and most of the research work has so far focused on providing security for routing using cryptography. In this paper, we propose a novel approach to secure Ad hoc On-demand Distance Vector (AODV) routing protocol from the insider attacks launched through active forging of its Route Reply (RREP) control message. AODV routing protocol does not have any security provision that makes it less reliable in publicly open ad hoc network. To deal with the concerned security attacks, we have proposed AODV Security Extension (AODVSEC) which enhances the scope of AODV for the security provision. We have compared AODVSEC with AODV and Secure AODV (SAODV) in normal situation as well as in presence of the three concerned attacks viz. Resource Consumption (RC) attack, Route Disturb (RD) attack, Route Invasion (RI) attack and Blackhole (BH) attack. To evaluate the performances, we have considered Packet Delivery Fraction (PDF), Average End-to-End Delay (AED), Average Throughput (AT), Normalized Routing Load (NRL) and Average Jitter and Accumulated Average Processing Time.Comment: 20 Pages, 24 Figure

NDTAODV: NEIGHBOR DEFENSE TECHNIQUE FOR AD HOC ON-DEMAND DISTANCE VECTOR (AODV) TO MITIGATE FLOOD ATTACK IN MANETS

ABSTRACT Mobile Ad Hoc Networks (MANETs

Levels of Recent Thymic Emigrant Cells Decrease in Children Undergoing Partial Thymectomy during Cardiac Surgery

The human thymus is required for establishment of a T-cell pool in fetal life, but postnatal thymectomy is not known to cause immunodeficiency. T-cell emigration from thymus (thymic recent emigrants [TRECs]) is a continuous thymic-dependent process. We studied TREC levels pre- and post-partial thymectomy in children undergoing cardiac surgery. TRECs were quantitated by real-time PCR in peripheral blood lymphocytes of 24 children (0 to 12 years). TREC values were 47916 ± 9271 pre-partial thymectomy and 33157 ± 8479 post-partial thymectomy in 11 paired patients (P = 0.014). Interval between pre- and post-partial thymectomy was 8.8 days ± 5.8 days. Another group of 8 children had 30384 ± 9748 TRECs 16 days to 6 years post-partial thymectomy. There was a significant drop in TREC values post-partial thymectomy in the immediate postoperative period compared to prethymectomy TREC levels. While decreased thymic output may persist, the long-term implications were not evaluated in this patient population