Modeling and Caching of P2P Traffic

Peer-to-peer (P2P) file sharing systems generate a major portion of the Internet traffic, and this portion is expected to increase in the future. The sheer volume and expected high growth of P2P traffic have negative consequences, including: (i) significantly increased load on the Internet backbone, hence, higher chances of congestion; and (ii) increased cost on Internet Service Providers (ISPs), hence, higher service charges for all Internet users.

A potential solution for alleviating those negative impacts is to cache a fraction of the P2P traffic such that future requests for the same objects could be served from a cache in the requester’s autonomous system (AS). Caching in the Internet has mainly been considered for web and video streaming traffic, with little attention to the P2P traffic. Many caching algorithms for web traffic and for video streaming systems have been proposed and analyzed. Directly applying such algorithms to cache P2P traffic may not yield the best cache performance, because of the different traffic characteristics and caching objectives. For instance, reducing user-perceived access latency is a key objective for web caches. Consequently, web caching algorithms often incorporate information about the cost (latency) of a cache miss when deciding which object to cache/evict. Although latency is important to P2P users, the goal of a P2P cache is often focused on the ISP’s primary concern; namely, the amount of bandwidth consumed by large P2P transfers. Consequently, the byte hit rate, i.e., the number of bytes served from the cache to the total number of transfered bytes, is more important than latency.

We are developing caching algorithms that capitalize on the P2P traffic characteristics. We are also exploring the potential of cooperative caching of P2P traffic, where multiple caches deployed in different ASes (which could have a peering relatioship) or within a lrage AS (e.g., a Tier-1 ISP) cooperate to serve traffic from each other`s clients. Cooperation reduces the load on expensive inter-ISP links. Furthermore, we are implementing all of our algorithms and ideas in a prototype caching system.

People

• Mohamed Hefeeda

• Cheng-Hsin Hsu (PhD Student)

• Behrooz Noorizadeh (MSc Student, Graduated Fall 2007)

• Osama Saleh (MSc Student, Graduated Fall 2006)

Publications

• M. Hefeeda and O. Saleh, Traffic Modeling and Proportional Partial Caching for Peer-to-Peer Systems, IEEE/ACM Transactions on Networking, Accepted October 2007.

• M. Hefeeda and B. Noorizadeh, On the Benefits of Cooperative Caching for Peer-to-Peer Traffic, Submitted for publications, 2008.

• O. Saleh and M. Hefeeda, Modeling and Caching of Peer-to-Peer Traffic , In Proc. of IEEE International Conference on Network Protocols (ICNP'06), pp. 249--258, Santa Barbara, CA, November 2006. (Acceptance: 14%)

Software

• coming soon ....

P2P Traffic Traces

• If you are interested in the traces, please send us an email along with a brief description of your research and the university/organization you are affiliated with. Brief description of our traces can be found in this readme.txt file.