JP wrote:

There are no such known limits. I might even go as far to say that there are no such limits, if I were feeling daring. :) Do you have a short program which demonstrates this behavior that you can share? Perhaps after looking at that someone can suggest the cause of the disconnects.

After looking into it some more myself i realised an uncaught exception was dropping the connection but the after cutting my test code back to minimal functionality the inconsistency with received data was still there. The last 4KB of the data was received and the first 14KB discarded somewhere! I have created a minimal example from my initial test code. Start the simpleserver with twistd.py -y simpleserver.py and just run the simpleclient.py the builder.dat file is just a nonsense file that is about 18KB in size. Testing on my machine produced a received.dat file which was 4KB in size. I am currently using Python 2.3.3 and Twisted 1.3.0. The code is as follows (and is also attached for convenient running): ### ------------ simpleclient.py --------------------------------- from twisted.internet.protocol import Protocol import twisted.internet.error from simpleprotos import SimpleClientFactory factory = SimpleClientFactory() # open a large nonsense file to send (18KB) f = file('builder.dat') data = f.read() print len(data) f.close() from twisted.internet import reactor reactor.connectTCP('127.0.0.1', 10000, factory) reactor.callLater(1.0, factory.sendMessage, data) reactor.run() ### ------------- end --------------------------------------------- ### ------------ simpleserver.py ---------------------------------- from twisted.application import internet # services that run TCP/SSL/etc. from twisted.application import service from simpleprotos import ServerDataConnection, SimpleFactory def makeService(): factory = SimpleFactory() # here we create a ConnectionManager return internet.TCPServer(10000, factory) application = service.Application("Connection Manager") sc = service.IServiceCollection(application) sc.addService(makeService()) ### ------------- end --------------------------------------------- ### ------------ simpleprotos.py ---------------------------------- from twisted.internet.protocol import ClientFactory, Factory, Protocol class SimpleClientFactory(ClientFactory): def buildProtocol(self, addr): self.p = ClientDataConnection() self.p.factory = self return self.p def sendMessage(self, data): if hasattr(self, 'p'): self.p.sendData(data) class SimpleFactory(Factory): def buildProtocol(self, addr): self.p = ServerDataConnection() self.p.factory = self return self.p class ServerDataConnection(Protocol): def closeConnection(self): self.transport.loseConnection() def dataReceived(self, data): f = file('received.dat', 'w') f.write(data) f.close() class ClientDataConnection(Protocol): def closeConnection(self): self.transport.loseConnection() def sendData(self, data): self.transport.write(data) ### ------------- end --------------------------------------------- Regards, Grant McDonald