Abstract
Accurately estimating network size is essential in unstructured peer-to-peer (P2P) networks. In previous studies, proposed sampling mechanisms for estimating network sizes assumed the probability that a peer is sampled is proportional to the number of its neighbors. This assumption leads to a sampling bias in favor of peers with many neighbors - something that commonly occurs in power law networks. To reduce this sampling bias, we propose a pheromone mechanism, that calibrates sampling probability by the amount of pheromone. This mechanism can be adapted to ex- isting size-estimation techniques. Our empirical studies show that by adapting the pheromone mechanism, most size-estimation techniques can be significantly improved (in some cases, by more than 100%).