Does Apple use TCP or UDP to deliver messages from its servers to the device?
From the Apple Push Notification Service Programming Guide :
Important: WiFi is used for push notifications only if there is no cellular connection or if the device is iPod touch. To receive notifications via Wi-Fi, the device's display must be turned on (that is, it cannot sleep), or it must be connected. The WiFi transmitter must be turned on with outbound TCP port 5223 and must be within the effective range.
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Sandbox and production environmentTo develop and deploy the provider side of the client-server application, you should receive SSL certificates from the iPhone Developer Portal. Each certificate is limited to one application, identified by its bunch of I would. Each certificate is also limited to one of two development environments, each with its own assigned IP address:Sandbox: A sandbox environment is used for initial development and testing of a vendor application. It provides the same set of services as the production environment, although with fewer server blocks. The sandbox environment also operates a virtual device that allows simulated end-to-end testing. You access the sandbox environment at gateway.sandbox.push.apple.com, outbound TCP port 2195.Production: use the production environment when creating the production version of the supplier expression. Applications that use the production environment must have apple reliability requirements. You access the production environment at gateway.push.apple.com, outbound TCP port 2195.
Sandbox and production environment
To develop and deploy the provider side of the client-server application, you should receive SSL certificates from the iPhone Developer Portal. Each certificate is limited to one application, identified by its bunch of I would. Each certificate is also limited to one of two development environments, each with its own assigned IP address:
Sandbox: A sandbox environment is used for initial development and testing of a vendor application. It provides the same set of services as the production environment, although with fewer server blocks. The sandbox environment also operates a virtual device that allows simulated end-to-end testing. You access the sandbox environment at gateway.sandbox.push.apple.com, outbound TCP port 2195.
Production: use the production environment when creating the production version of the supplier expression. Applications that use the production environment must have apple reliability requirements. You access the production environment at gateway.push.apple.com, outbound TCP port 2195.
finally:
General Supplier RequirementsAs a provider with whom you can communicate with Apple Push Notification Service over a binary interface. This interface is a high-speed high-capacity interface for suppliers; It uses a streaming TCP socket design combined with binary content. The binary interface is asynchronous.The binary production environment interface is available through gateway.push.apple.com, port 2195; sandbox binary interface (development) of the environment through gateway.sandbox.push.apple.com, port 2195. You can establish multiple concurrent connections to the same gateway or multiple gateway instances.
General Supplier Requirements
As a provider with whom you can communicate with Apple Push Notification Service over a binary interface. This interface is a high-speed high-capacity interface for suppliers; It uses a streaming TCP socket design combined with binary content. The binary interface is asynchronous.
The binary production environment interface is available through gateway.push.apple.com, port 2195; sandbox binary interface (development) of the environment through gateway.sandbox.push.apple.com, port 2195. You can establish multiple concurrent connections to the same gateway or multiple gateway instances.