Nodes cut off by all neighbors are effectively cut

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ill-effects of malicious nodes. Nodes cut off by all neighbors are effectively cut off from the subnet. Maintaining a logical neighborhood is advantageous for dense neighbor- hoods. In a region where a node A has 100 nodes within range, A may decide to include only 10 of them in its logical neighborhood as 10 neigh- bors may be sufficient to provide A with connectivity to all other mobiles or the gateway. Such an approach is also useful in scenarios involving highly dynamic nodes. Consider a scenario where a mobile device in a fast moving vehicle sends a RREQ packet. If every neighbor simply floods the RREQ Copyright © 2010. World Scientific Publishing Company. All rights reserved. May not be reproduced in any form without permission from the publisher, except fair uses permitted under U.S. or applicable copyright law. EBSCO Publishing : eBook Collection (EBSCOhost) - printed on 2/16/2016 3:46 AM via CGC-GROUP OF COLLEGES (GHARUAN) AN: 340572 ; Beyah, Raheem, Corbett, Cherita, McNair, Janise.; Security in Ad Hoc and Sensor Networks Account: ns224671
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Key Distribution 61 onwards it may result in substantial wastage of bandwidth as the RREQ source is very likely to have moved away from the location the RREQ orig- inated by the time the response (RREP) comes back. If nodes enforce a logical neighborhood (and induct nodes in their logical neighborhood only after a few exchanges) only nodes moving at roughly the same speed (or relatively stationary to each other) will form an exclusive network. Thus a set of northbound vehicles in Interstate I-95 may form an ad hoc subnet that excludes all southbound vehicles (and vice-versa). Mandating a logical neighborhood can also deter selfish behavior. For example, a selfish node C may remain silent and not participate in the routing process unless it hears a RREQ addressed to C , or if C needs to send a message. When a logical neighborhood is enforced C will have to be inducted into neighborhoods of other nodes before C can monitor traffic. Once inducted, a node C is pressured to participate to the fullest extent due to the fact that it is under constant observation by its neighbors, who may cut C off if they sense non-participation of C . 5.3.2. User-Agent One-Hop Signatures While there are compelling reasons for network agents to avoid asymmetric primitives for authenticating routing packets, user agents can use asymmet- ric primitives. Consider a scenario where a node A detects an inconsistency in a packet received from some node C . More specifically, assume that A recognizes that the authentication appended by B (where B is a two-hop neighbor of A and a one-hop neighbor of C ) is inconsistent with the routing information supplied by C . In such a scenario, the best that A can do is to suspect that either B or C may be malicious, and drop the inconsistent packet.
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