TCP/IP is a protocol stack for communication, a socket is an endpoint in a (bidirectional) communication. A socket need not be TCP based, but it is quite often the case. The term socket is also often used to refer to the API provided by the operating system that allows you to make a connection over … Read more
Message Oriented protocols send data in distinct chunks or groups. The receiver of data can determine where one message ends and another begins. Stream protocols send a continuous flow of data. Here is an example with mobile phones. Text messages would be a message oriented protocol as each text message is distinct from the other … Read more
The format and size of the address is usually protocol specific. sockaddr is used as the base of a set of address structures that act like a discriminated union, see the Beej guide to networking. You generally look at the sa_family and then cast to the appropriate address family’s specific address structure. TCP and UDP … Read more
I learned IP networking from TCP/IP Illustrated. Highly recommended.
If you are 100% certain that the programs that are going to communicate over ZMQ will at all times be capable of understanding each other’s binary format (eg because they are always distributed together and were all compiled with the same compiler options anyways) I see no benefit to the overhead that’s added by serialization. … Read more
This is a pretty broad question and its treatment likely requires a fairly dense book. I don’t know of any such resource myself, but lets think this through and consider what would be the dimensions of a network communication pattern space: connection modality: { connection-based, connection-less} interaction modality: { synchronous, asynchronous } conversation complexity: { … Read more
In theory SMTP can be handled by either TCP, UDP, or some 3rd party protocol. As defined in RFC 821, RFC 2821, and RFC 5321: SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. In addition, the Internet Assigned Numbers Authority has allocated port 25 for both … Read more
If it is just an edge case problem, then using a http fallback might be your only option. I guess you already do this for proxy servers that block socket connection away.
I’m not aware of any nameservers that support multiple questions in a single query. There’s potential for ambiguity in such a query, since there are per-packet flags (such as AA) which could apply to only one of the questions. If you ask two questions and the server is authoritative for only one of the domains, … Read more
HTTP is a stateless protocol, in other word the server will forget everything related to client/browser state. Although web applications have made it virtually look like stateful. A stateless protocol can be forced to behave as if it were stateful. This can be accomplished if the server sends the state to the client, and if … Read more