The MacBook Air, announced at Macworld, is now shipping. The included “Remote Disc” software adds a new service to the Sharing System Preferences of other machines on your network. Not much is known about “DVD or CD Sharing,” but the MacBook Air User’s Guide makes it clear that this is one of the methods by which a Mac (or Windows machine) makes its optical drive available to the MacBook Air over your local network.

After installing special software (included with the Air) and activating “DVD or CD Sharing” on the “other computer” (which, if a Mac, must be running Mac OS X 10.4.10 or later), that machine’s remote optical drive appears in the Finder sidebar on the MacBook Air. It can then be accessed just like any other local disk or shared machine.

Some interesting questions include:

1. • How is the service implemented? Does it use TCP or UDP, and what port number(s)? How can you safely limit access to the service (via either the built-in firewall, which is quite different depending on if it’s on 10.4 or 10.5, or a third-party firewall)?
   

2. • Will the service only make the drive available to MacBook Airs, or will there be a Leopard upgrade that makes it available to other Leopard Macs as well?
   

3. • Do other remote optical drive features, like migration assistant and remote booting, work differently (from a network perspective)?