We are currently working on integrating sales force mobile push sdk in our android app. We have the salesforce sdk returning the device token and also we are able to trigger the push notification. But we are interested in knowing about how does the sales force's send push notification rest api call (with the device token in the request) internally talks to the appropriate vendor(Google/Apple) to trigger push notification to the device? Do you call the GCM/APNS push notification apis from sales force along with the device token to trigger push notification? . Also please let us know the complete push notification flow after the send push notification api request reaches sales force?
Salesforce's push servers use the device's token with GCM or APNS to deliver push messages.
You're going to have to be more specific about your 2nd question.