[Show abstract][Hide abstract] ABSTRACT: Lookup is crucial to locate peers and resources in structured P2P networks. In this paper, we measure and analyze the traffic characteristics of lookup in Kad, which is a widely used DHT network. Some previous works studied the user behaviors of Kad, yet we believe that investigating its traffic characteristics will also be beneficial, as it gives feedbacks to fine tune the system parameters, helps to uncover the abnormalities or misuses, and provides solid ground for synthesizing P2P traffic to evaluate future designs.To track the lookup requests more efficiently and from more peers in Kad, we develop an active traffic monitor, named Rememj. From the one-week data it collected, we uncover some interesting phenomena. Moreover, we characterize the traffic characteristics from the collected data in a form that can be used for constructing representative synthetic workloads for evaluating DHT optimizations or designs. In particular, the analysis exposes heterogeneous behavior that occurs in different geographical regions (i.e., Europe, Asia, and America) or during different periods of the day. The workload measures include distribution of peers, distribution of request load, distribution of targets, as well as similarity among targets.
No preview · Article · Aug 2011 · Computer Communications
[Show abstract][Hide abstract] ABSTRACT: DHTs have been widely used in designing various applications, especially P2P file sharing systems. It is crucial but difficult to get an accurate snapshot of a DHT network, since such network is serverless and peers join and depart dynamically. In this letter, we analyze and empirically verify that neither breadth-first search nor depth-first search is optimal for DHT snapshot crawling, due to uneven ID distribution of contacts in the routing table of each DHT peer. We then propose a hybrid search strategy which could both start up quickly and slow down slowly. The experiment performed on Mainline shows that this approach significantly outperforms breadth-first or depth-first search strategy.
No preview · Article · Feb 2011 · IEEE Communications Letters