Why does the native SIP stack included in Android 2.3 does not work over 3g?

Question

I was wondering why does the native SIP stack included in the Android framework(since 2.3) does not work over 3g?

Could it have something to do with any laws or restrictions google may have with his partners?

And furthermore, does anybody know if there is any plans to remove that restriction ?

Thx

There may be restrictions imposed by your carrier. Many VOIP apps use SIP to negotiate the end to end connection and some carriers will block SIP altogether to prevent this. — Mark Allison, Jun 03 '11 at 14:41
Yeah for sure, but in this case, SIP calls work with other sip stacks in other software: SIPDroid, CSIPSimple etc. So its really a restriction in the android sip stack. — clauziere, Jun 03 '11 at 18:54
Are you using stock firmware? It might be crippled by the MNO. Some simply remove it. Third party stacks are not part of the OS, and are thus not modified and should work as long as the MNO is not explicitly blocking SIP ports, etc. Try it out with a Nexus device or CyanogenMod ROM. — Nikolay Elenkov, Dec 21 '12 at 09:00

score 8 · Accepted Answer · answered Dec 22 '12 at 05:34

In GingerBread, SipManager is set to work only on wifi.

`<bool name="config_sip_wifi_only">true</bool>`

But from 4.0 onwards, this config has been changed to false

So Ideally native sip stack should work on 3G from Ice Cream Sandwich onwards.

But again if the phone is sold by a service provider, then this might have been disabled. So phones sold unlocked may have this intact.

To check whether Sip over 3G is supported you can use the api

   SipManager.isSipWifiOnly(mContext);

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