CommCenter is the service handling network connectivity on the iPhone, iPad and iPod touch.
Disabling CommCenter (
launchctl unload -w /System/library/LaunchDaemons/com.apple.CommCenter.plist) will result in the loss of cellular-related services until CommCenter is restarted. Examples of this include variations in the Settings app due to the inability to load a carrier bundle, the "Searching..." message on the status bar and an empty badge (undetermined amount of new voicemail) on the Phone app.
Beginning with iPhone OS 2.0, stopping CommCenter will also result in a loss of Wi-Fi networking until the device is rebooted.
People make "CommCenter patches" for jailbroken devices to change various settings.