Is Android app upstream messaging reliable?

Question

I want to use ccs upstreaming messages to send the messages from my application to the app ccs server. I have written the code for ccs app server and its connected to the gcm server. Sometimes the sent messages are delivered to server quickly like instant but most of the times they dont. All my messages contain the ttl as 0 in the gcm.send() function. If i try to send more messages with ttl 0 gcm gives "Too Many Messages error". Is there any way to find whether the sent message via upstream method is delivered to ccs server(any ack to client app even before the message reaching the our xmpp app server) ? How the gcm client deals with the ttl's of different messages. ( lets say first 10 messages does not have a ttl and 11th message has a ttl of 5 and after that 2 messages with ttl 0 ). How are these messages going to be delivered to the ccs server in which order if all the messages sent continuously in less than 5 seconds(like all at at time) ?

Thanks, SM

Answer 1

As with downstream messages, an upstream message with a ttl=0 is sent immediately, or never, depending on the network state, and the connection between GCM device-client and CCS server.

I describe here a related issue concerning some previous android versions.

Short answer: upstream messaging are reliable in KK, not on previous versions.