這陣子，公司在評估一些 iphone app 的解決方案，找到了下面這一個IOS上面的推播技術-Apple Push Notification Service，但是感覺在實作時如果不採用一些其他的雲端服務而想自行開發，感覺開發成本好高

Apple Push Notification Service (APNs for short) is the centerpiece of the push notifications feature. It is a robust and highly efficient service for propagating information to devices such as iPhone, iPad, and iPod touch devices. Each device establishes an accredited and encrypted IP connection with the service and receives notifications over this persistent connection. If a notification for an application arrives when that application is not running, the device alerts the user that the application has data waiting for it