在同一个应用程序中使用TCP和UDP的任何问题？

Question

The point of my question is to ask if it is accepted to use both TCP and UDP to communicate between client and server.

I am making a real-time client server game with parts of the communication that need to be guaranteed (logging in, etc..), but other parts will be ok to lose packets (state updates, etc). So, I would like to use UDP for most of the data communication but I do not want to have to implement my own framework to insure that my control communication (logging in) is guaranteed.

So, would it be reasonable to initially use TCP to manage a connection, and then on a separate port send data communication pack and forth?

Answer 1

You should absolutely do it that way (use TCP and UDP to accomplish different communication tasks.) And you don't even have to use two different ports. One will suffice . You can listen to the two different protocols on the same port.

Answer 2

It is quite reasonable and already used in mainstream. Even when browsing the Web, DNS operations are UDP-based and HTTP connections are TCP-based.

Keep in mind that you should either consider the two connection types to be completely independent or employ additional measures to properly handle any inter-dependencies. TCP connections can have timing issues at the OS and network levels and UDP connections have packet loss issues. You should take specific measures to avoid deadlocks and performance problems when the TCP part of your application stalls or a UDP packet is lost.

Answer 3

It is not only accepted but is widely used. As a good example, BATS Exchange is using this approach in their market data distribution system, to implement a recovery mechanisms.