About Apple Push Notification Service(转)
转自http://support.apple.com/kb/HT3576
About Apple Push Notification Service
Summary
Apple Push Notification Service is available for applications on the following devices:
- iPhone
- iPad
- iPod touch
This article explains the basics of push notifications and where to get additional information.
Products Affected
iPod touch, iPhone, iPad
Apple Push Notification Service requires iOS 3.0 or later and a connection to the Internet, either via a cellular data network or Wi-Fi, and at least one application that supports notifications.
- If the Settings > Notifications menu does not appear on your device, you don't have an application installed that supports notifications.
- You need to open an application at least once to get any notifications from that app.
- When the iPod touch screen is on and has a Wi-Fi connection, push notifications are received at any time. If the iPod touch screen is asleep, it will check every 15 minutes for a notification.
- If you want to disable notifications from an application, turn off all notifications for that application in Settings > Notifications.
- When you restore a backup to a different iPhone or iPod touch, apps will need to be opened again to get notifications.
- If the device is connected over Wi-Fi and is still unable to receive notifications, the Wi-Fi network you're using might have a firewall that is blocking port 5223. This port must be open to TCP traffic for notifications to work.
For additional information, refer to the User Guide for your device.
Additional Information
Applications can offer up to three types of push notifications:
- Sounds: Plays an audible alert
- Alerts: Displays an alert on the screen
- Badges: Displays an image/number on the application icon
