How it works with Blackberry is that channel pushes, notification pushes and application / content pushes all are initiated by a web service call. The XMl spells out who gets it. So the path is just like any other network path - it's server to client - where the client has a PIN or Mac Address providing some unique destination. With no infrastructure that I'm familiar with for the iPad, I can't say it's similar but I would guess somewhere in the bowels it's the same approach.
How it works with Blackberry is that channel pushes, notification pushes and application / content pushes all are initiated by a web service call. The XMl spells out who gets it. So the path is just like any other network path - it's server to client - where the client has a PIN or Mac Address providing some unique destination. With no infrastructure that I'm familiar with for the iPad, I can't say it's similar but I would guess somewhere in the bowels it's the same approach.