Feature Requests item #454626, was opened at 2001-08-23 09:27 You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=376688&aid=454626&group_id=22866 Category: None Group: None Status: Open Priority: 5 Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: replicated cluster Initial Comment: I have written a Java implementation of the TOTEM protocol, as published by a research group at UCSB. The protocol has several features: 1. Messages are multicast, rather than sent point-to- point, leading to good scalability with respect to the number of receivers. 2. It is reliable. Endpoints in the protocol form a group, and the protocol enforces that either all members of the group receive a message, or the members that did all failed. Retransmission of dropped messages is done using NAKs rather than ACKs. 3. All members of a group deliver the messages to the application in the same order. This (a.k.a. total ordering) is implemented using a rotating token. 4. It has an effective flow control algorithm. The flow control information is piggybacked on the token. Because on small LANs most messages are lost because of buffer overflow, flow control is the determining factor in the ultimate performance of the protocol. Basically it works so well that hardly any messages are ever dropped. 5. The last feature is my own humble contribution to this protocol. Because the flow control put in by UCSB requires a window size to be tuned by hand, I put in a form of congestion avoidance and control algorithm that dynamically tunes the window size. So no tuning is needed. The algorithm is based on the CAC algorithm used in TCP. I implemented this in Java after spending months researching how to best use multicasting to write a coherent cache for a job I was doing. On my 455Mhz pIII it performs at about 4000 1kb messages per second. I was going to build other things on top of it, like a replicated EJB server, but the fun part was the protocol, and I have kind of lost interest. However, you already have an EJB server. If you can see how to use this protocol to your advantage, and you have someone to devote to working on this, I am interested in talking to you. Best regards, Guglielmo ---------------------------------------------------------------------- You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=376688&aid=454626&group_id=22866 _______________________________________________ Jboss-development mailing list [EMAIL PROTECTED] http://lists.sourceforge.net/lists/listinfo/jboss-development
