This is my personal blog. The views expressed on these pages are mine alone and not those of my employer.

Saturday, January 31, 2004

Kelips: Building an Efficient and Stable P2P DHT Through Increased Memory and Background Overhead

Overlook: A Scalable Name Service on an Overlay Network: "This paper presents Overlook, a scalable fault-tolerant name service that is built on top of a P2P overlay routing network (Pastry). The basic motivation behind the paper is that existing scalable name services like DNS cannot be suited to applications like Herald, an Internet-scale event notification service, where a) updates have to be made globally visible in seconds, and b) flash crowd (sudden surge in the popularity of one or a few names) is a common occurrence This is because existing name services rely on fairly static sets of data replicas and client-side caches. Overlook tries to address these issues by allowing dynamic addition and deletion of data replicas in response to varying popularities of events."

FreePastry: "FreePastry is an open-source implementation of Pastry intended for deployment in the Internet. The initial release of FreePastry is intended primarily as a tool that allows interested parties to evaluate Pastry, to perform further research and development in P2P substrates, and as a platform for the development of applications. Plans for later releases are to provide a robust, fully secure implementation that is suitable for a full-scale deployment in the Internet."

Found a great page that describes several distributed hashtable systems that are attempting to achieve O(1) lookup for DHTs; this is important because decreasing latency in DHTs makes them more viable for replacing DNS and acting as a general P2P substrate. Here is an example from the page: CS 615: Disributed hash tables (structured O(1)).: "The key idea is that a lookup time better than O(log n) can be achieved at the cost of increased storage and traffic overhead. The system presented in this paper achieves the O(1) lookup performance at the cost of roughly O(sqrt(n)) storage per node, less than 2MB in an experimental system of 100 thousand nodes storing 10 million files used in the tests......A high-churn scenario was also tested, half of the nodes were randomly chosen to fail. It appeared that queries would only fail if the home node failed, which indicates that the system is still able to efficiently route messages in such situation."

Doug's Inner Net News: SIP and JXTA: "SIP is complex. JXTA is relatively simple. I'm not exactly sure why that is so. SIP is used for call control in IP telephony, and call control in the PSTN is complex. But I have to wonder if SIP would not have been simpler if it had started with a model of peer-to-peer communication like that in JXTA. If I were to start work on a new peer-to-peer protocol, I would consider building upon JXTA."

P2P Framework: "The OogP2P framework is a framework for developing and running applications on a peer-to-peer system. The OogP2P framework is designed in such a way that users can develop and run new applications while having to add a constant, O(1), amount of code to the existing framework, without any modification to pre-existing applications running on the system, and without any modification to the network model. Applications are not limited to programs such as file sharing, chat, and networked games, but also include peer-to-peer components such as algorithms for searching, load balancing, and network-data gathering, to name a few. Developers can create applications by following the Communication and Application Architectures as specified in our papers." Need to look at this some more; evidently they looked at JXTA and decided to roll their own solution. The OogP2P folks found the following problems with JXTA (taken verbatim from their presentation):

I've looked over the OogP2P framework and it doesn't seem any easier than JXTA; it's pretty obtuse. - Sun Sends P-to-P to Work: "Verizon explored other technologies, including Gnutella and some peer-to-peer tools that Microsoft recently introduced. It picked Jxta mainly because 'it's very extensible--there aren't a lot of restrictions on how we run our applications,' Minwalla says. It also liked that the software is open source, and that it can handle firewalls and NATs straight out of the box, he says."

America Enjoys Rich History of Election Hijinks: "A favored 19th century technique for spicing up a campaign went as follows: An office-seeker walked along a country road and saw a farmer plowing his field so far in the distance that the two men could barely make each other out. “Halloa,” the candidate shouted, “I’m John Smith, I’m running for mayor. Vote for me. That’s a good fellow.” Then he waved to the farmer and kept on walking. Except it wasn’t John Smith; it was his opponent, Tom Brown. Later in the day, Brown came by again, this time identifying himself correctly, and heading into the field to help the farmer with his plowing. The farmer reacted predictably, admiring Brown for his work ethic while cursing the idler Smith, for whom he would not now vote under any circumstances."

This page is powered by Blogger. Isn't yours?

Subscribe to Posts [Atom]