Extend TCP Keep Alive intervals

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Nature of the app

What is the expected output? What do you see instead?
Referencing http://code.google.com/p/sipdroid/wiki/NewStandbyTechnique, typical 
TCP timeout values are 30-1440 minutes. The assumption that that sipdroid will 
have a long interval between sending keep alive packets for TCP. However, I'm 
seeing that it's fixed at 60 seconds still. I searched other issues and found 
it mentioned but not posted as an issue. I had assumed that sipdroid would be 
using a longer tcp keep alive interval.

What version of the product are you using? On what device/operating system?
Latest 2.9 on a Nexus 4 running 4.2.1.

Which SIP server are you using? What happens with PBXes?
pbxes.com

Which type of network are you using?
tcp connection to pbxes over wifi (nat)

Please provide any additional information below.
I have confirmed with BetterBatteryStats that there is a wakeup event triggered 
by sipdroid every 60 seconds.

Original issue reported on code.google.com by zid...@ijib.com on 24 Jan 2013 at 8:43

[GoogleCodeExporter]

I also have the same pattern of wakes. In CSipSimple, I'm able to to set the 
TCP KA packet interval to 600 seconds with Pbxes.org. It would be helpful to be 
able to control this in SipDroid as well.

Original comment by luciddef...@gmail.com on 14 Feb 2013 at 12:16