I read that is possible to set up a Network Hard Disk in order to connect it to the router and perform wireless Time Machine backups on the Hard Disk.
What are the pros and cons of using a Network Hard Disk rather then Time Capsule?
I found this in the help (Mountain Lion) ...
If your backup disk is on a network, the network server must use Apple File Protocol (AFP) file sharing, and both your computer, and the networked backup disk, should have Mac OS X 10.5.6 or later. The AFP disk must also be “mounted” (available to your computer).
Note: Some AFP disks from manufacturers other than Apple don’t support Time Machine. If your network uses an AFP disk, but the disk doesn’t appear in the list of devices available for Time Machine backups, contact the disk’s manufacturer.
I had my Buffallo NAS configurated as Time Machine Backup NAS. From one to the other TimeMachine told me that the Backup Volume was corrupt and could not be recovered. Possible Reason for the corruption is the filesystem, which had not the full capability of ntfs or mac os extended.
Right now I try to use a Synology NAS which has a build in TimeMachine support.
But if you want to be on the save side with your backup I would advice you to buy a TimeCapsule which has the best compatability with the TimeMachine.
Time Machine uses HFS+ features, so you can't just share a random third-party filesystem and have it work correctly.
If you do want to use a shared filesystem, you are best off creating a disk image on the filesystem, creating an HFS+ filesystem in the disk image using Disk Utility, and then having Time Machine use that.