Abstract: Wireless ad-hoc networks emerged as a promising technology that offers low-cost high-bandwidth community wireless services. A WAN consists of a set of stationary wireless routers that form a multi hop backbone, and a set of mobile clients that communicate via the wireless backbone. Many applications can benefit from the service provided by multicast routing protocols. In a typical high-throughput multicast protocol, nodes periodically send probes to their neighbours to measure the quality of their adjacent links. During route discovery, a node estimates the cost of the path by combining its own measured metric of adjacent links with the path cost accumulated on the route discovery packet. The path with the best metric is then selected. ODMRP, as it is a ad-hoc based protocol, which has the potential to be more attack resilient. We focus on the SPP metric based on the well known ETX unicast metric. We identify a class of severe attacks against multicast protocols that exploit the use of high-throughput metrics, including local metric manipulation (LMM) and global metric manipulation (GMM). We propose a secure high-throughput multicast protocol S-ODMRP that incorporates a novel defense scheme Rate Guard. Rate Guard combines measurement-based detection and accusation-based reaction techniques to address the metric manipulation and packet dropping attaciks.Sybil attack detection, Detection Algorithm is used to detect the Sybil attack. And individual nodes that wish to detect Sybil attackers monitor all transmissions We receive over many time intervals. These intervals are chosen long enough to capture behaviour from all the Sybil identities of an attacker, including data transmissions, HELLO and keep-alive messages, and routing requests and replies. The node keeps track of the different identities heard during the interval. Having made many observations, the node analyzes the data to find identities that appear together often and that appear apart rarely. These identiti