How to let different processes use different network interfaces?
network-programming, networking, sockets
Solution
If your goal is to increase bandwidth to the server by using multiple network interfaces in parallel, then that's probably not something you can (or should) do at the application level. Instead, you should study up on Link Aggregation and then configure your computer and networking stack to use that. Once that is working properly, you will get the parallelization-speedup you want automatically, without the client application having to do anything special to enable it.
Problem
I'm on the client side. There're multiple network interfaces. How can I let different processes use different network interfaces to communicate? Since I want to connect to the same server, routing seems not working here. Also, `connect()` doesn't have arguments to specify local address or interface as `bind()` does.