Question(s) about apps that use wifi to remotely access clients on a 802.11 router

So there are a few apps on the app store that implement access to machines that are on a wireless network through the router. Apps such as Apple's own Remote app that lets you control the music on the computer remotely through wifi. Or another app even more amazing, WifiRemote takes that to the next level and lets you control your whole computer from your iphone! wow.

So now to my question(s), pardon my boring intro. How does this work? Obviously there is a wifi module on the iphone that connects wit开发者_StackOverflow社区h the wifi module on the router, that makes sense.

1. Does the router track how many clients or devices it has running on it by IP address or MAC address?

2. Is there a set limit of how many clients a router can typically support, or does it vary by the router?

3. Are there Wifi API's in the iphone sdk that allow you to easily connect to and communicate with the router?

4. What is the process behind connecting to the router, and then more specifically, the computer or hardware device you want to?
5. Once that connection has been established, how do you send commands to the client OS and tell it what to do!? Does it require some nitty gritty deep down background OS programming?

There are many more questions I have, but we'll just leave it at that :) As you can see, I'd really like to get my arms around this concept, of over the wifi network remote access, because it is so intriguing! Any and all answers/comments/links/references anyone has to offer would be greatly appreciated! I am here to learn. Thanks!

The apps use Bonjour to communicate over a local network. The Bonjour API makes this kind of thing really easy accomplish.

Bonjour Programming Guide