Changing TCP socket buffer sizes on macOS

With

NWTCPConnection

I don't see any option to get socket FD and override the default values

You are assuming that there is an underlying file descriptor, which is not always true. Depending on the system release,

NWTCPConnection

might route through to the kernel networking stack via BSD Sockets or to the user space networking stack via Network framework.

As to your overall goal,

NWTCPConnection

is a relatively lightweight API and it does not let you control low-level features like the socket buffer size. As to whether Network framework exposes these, I’m not sure. I had a quick look and couldn’t find anything obvious.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Ok thanks Quinn, we are trying to changes the buffer sizes in "/etc/sysctl.conf" and see if it causes any improvement. Those settings would be still used by "NWTCPConnection", right?

As to whether Network framework exposes these, I’m not sure.

Wow, there it was, hiding in plain site. Check out the

availableSendBuffer

and

availableReceiveBuffer

properties on

NWProtocolTCP.Metadata

.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Thanks Quinn. But this is read only property for inspection purpose right?

But this is read only property for inspection purpose right?

Right. Sorry about the bum steer; somehow I’ve managed to end up chasing my own tail.

I’ll dig into this again and try to follow-up here with the results.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Ok thanks Quinn for detailed info.