The Socket link must be used both on and off the line.
Conclusion:
> SocketTheoreticallyOnly uplink or downlink is supported.
> The heartbeat packet must be upstream or downstream-Heartbeat packet request (upstream)-Heartbeat packet response (downstream ).
> If only one-way links are provided for a long time (only sending is not accepted, or only sending is accepted), the router discards the Socket data.
> Heartbeat packets are not required-any combination of up and down lines can maintain the effectiveness of the software (operating system, Program) and hardware (computer, router, and mobile phone base station) required by the Socket.
Related links:
Http://www.cnblogs.com/lcw/p/3565459.html
Case:
> The mobile phone sends 100 MB of files (upstream, only sent, not accepted) through Socket fragment. The average time consumption is 3 ~ 5 minutes.
> Occasional exception: the data received by the server is suddenly lost.
> If several NULL bytes (downstream) are reverse sent after each segment of the file is sent, the occasional exception disappears.