Hello, Tony. Tony Gravagno opined... >Clients need to know the port of a server, so a server >absolutely requires a fixed and well-known port.
A server can have a randomly assigned port that is fixed and well-known only between the client and the server. If the server only exists for the benefit of one client, it is up to them to figure out how to assign and communicate the port dynamically. The fixed and well-known port requirement does not imply that the assignment is permanent. >Why do you need an assigned port for a server? Think about the problem of a client needing to spawn a unique server on demand of the client. Each client may spawn a server dedicated to that client. Certainly if one were using real UNIX/Windows processes, one could single-thread through a central process and fork a new process, however, U2 products do not allow forking of processes. >> 2) The other issue with the initServerSocket() is that it >> does not recognize when another process already has a >> given port open for listening. > >I haven't read the specs for initServerSocket but if it >doesn't return a non-zero for an attachment failure then >yes, it's probably broken. Yep. >However, in general, a given service should only have one listening >process. Not always true. There are dynamic services too. >It is valid to have a range of ports which all >respond to inbound connections as a single service - that >is, multiple servers will be listening to different socket >ports, even if they support the same application/transport >service. Interesting idea but it does not help with this issue. Have you tried supporting multiple listening sockets in U2? You can not get anywhere without a select() or poll() function analogue. While one could spawn numerous phantoms, each listening on a unique port, one is left with how to coordinate data and such between the phantoms. Not a pretty solution. >Coordination of what ports are in use for a given service >should be done by the application, so you should never really >get to a failure in initServerSocket. Try the replication program using port 80. On my system initServerSocket returns success even though IIS is currently bound to that port. >If nothing else you can use netstat to see what ports are in >use and use a recognized port that is unallocated. Yes, but not a solution for this issue. >Again, if you randomly generate a socket port for a service, >how will any client know what port to connect to? They communicate the port number behind the scenes. >Good luck. >Tony Gravagno Thanks, Tony. Best regards, Gyle ------- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
