Voip on mobile data service

Could someone please explain (in simple terms!) why many mobile networks do not offer VOIP services?

Edited by mikejp (Mon 02-Oct-17 10:02:12)

Cuts into their call revenues - at least that is what it used to be a few years back. Plus mobile telephony is probably more reliable than data services and will work on a weaker signal.

Are you asking why they don't use VoIP to carry their telephony services or why they don't allow you to use VoIP on their data service?

NO 2. I'm not sure which 'call revenues' it is cutting into? After all, the customer has to buy data to use a VOIP service.

May I ask a supplementary, how do they block it? Is it by port blocking?

I have 'tidied up' my speeling on the thread title!

Edited by mikejp (Mon 02-Oct-17 10:06:38)

A few years back it was blocked because they made high call rates from mobile and international calls - why would someone pay for international call rates if they could use a relatively small amount of data over VoIP. Of course since then facetime, whatsapp, etc have all got much bigger and so the case is probably different now.

But, some mobile companies haven't decided to change the model yet.

Blocking is possibly done at protocol level - they will be monitoring for the specific protocol over any port so just changing port may not do anything to help (this is the same sort of blocking/prioritising that some ISPs such as PlusNet use).

Thanks, very helpful. Hopefully this useful addition to mobile facilities will become widespread. Certainly a couple of providers I have contacted are 'looking at it'.