5/83.4.3.3 The HG-CSP Connection
After a TCP connection to the well-known port 418 on a Hyperwave server is established, some negotiation between the client and the server is necessary. First, the data exchange mode is negotiated, either readable text or binary. Second, the byte order is fixed because some platforms have the least significant bit as the first bit of a byte, whereas others have it as the last. Finally, the client can decide whether it wants to access the server in distributed or local mode (see Section 3.4.2.1). Then the client signals the server that it is ready to receive messages and version of the HG-CSP it can understand.
After the negotiation process the client can send arbitrary commands to the server to identify, retrieve objects, perform searching etc., and wait for the server's reply. The server, on the other hand, can also send messages to the client without a prior request.
The session stays open until the TCP connection is closed, or the server drops the connection because the client has not sent any message for a set period of time (typically 10 minutes).