Cognitive radio is a emerging technology to solve the problems of spectrum inefficiency, and scarcity by providing the
vacant channel to the secondary users without disturbing the primary users. This paper presents Gymkhana, multi path route
discovery algorithm for cognitive radio mobile ad hoc networks. Data traffic congestion in the network can be avoided by
reducing the number of paths from source to destination. From the result of the routing algorithm trust value can be calculated.
In the proposed trust based CR-MANET routing protocol, the trust model involves two components: trust value from direct
observation and trust value from indirect observation. With direct observation from an observer node, the trust value calculated
using Bayesian inference, which is a type of uncertain reasoning when the full probability model can be defined. On the other
hand, with indirect observation, the trust value is obtained from neighbor nodes of the source of Secondary user, the trust value
is derived using the Dumpster-Shafer theory, which is another type of uncertain reasoning Combining these two trust values,
obtain more accurate trust values of the observed nodes in CR-MANETs