What is the gprs? i WOULD LIKE TO use a GPRS network?

Does an open socket use network bandwidth?

• Hi, If I have an application that keeps a socket open to a server, but is not sending or receiving data, does this still use some network bandwidth? If so, how much? I'm wondering if there is any overhead in just keeping the socket open, with both ends knowing that the connection is still there... does this use any network traffic for heartbeats or something like that? The reason I'm interested is that I want to keep a connection open to a mobile GPRS device where I have to pay by the amount of bandwidth I use. I'd rather not continually open and close the sockets, as this will have an overhead itself. So I'm hoping that the overhead for an unused socket is fairly low. thanks, Richard

• Answer:

  Hi Richard, According to the UNIX Socket FAQ on UNIXguide.net, "by default, no packets are sent on the TCP connection unless there is data to send or acknowledge." This has been true in my experience too. http://www.unixguide.net/network/socketfaq/2.8.shtml As the FAQ answer explains, there is a socket option SO_KEEPALIVE, which, if turned on, will generate heartbeat packets. There's another answer on this option. http://www.unixguide.net/network/socketfaq/4.7.shtml Although sockets implementations typically work this way, I don't think it is guaranteed by any standard, so it would be safest to test this with your software in your environment, as crythias suggested. With a good monitoring tool, you should be able to monitor just your one connection and not have to discount network traffic from other processes. Note that you may have to wait two hours or more to see a packet generated by the SO_KEEPALIVE option. I hope this is a satisfactory answer to your qestion. If you need any more information, please ask for a clarification. --efn