This article about overseas carriers blocking voip calls is worth a read.

http://www.spectrum.ieee.org/oct05/1846

Edited by Dave: Link corrected

VoIP has been around for years - as has other cheap calling methods such as calling cards and call-back etc...

Some countries such as Saudi Arabia and Pakistan always try and protect their state monopoly of telecoms by attempting to block such services. This has gone on for a long time.

But it's one thing for a country or individual ISP to attempt to block VoIP - but quite another for the web itself to block VoIP. The web is open and free; and thousands of large corporations route web calls internally via the net.

There have been attempts in the USA by ISP's to block VoIP calls - but the FCC has come down on them like a ton of bricks:

http://www.tmcnet.com/tmcnet/articles/2005/voip-call-blocking-fcc-madison-river-...

Yes, there is no reason why an ISP in the UK can refuse to allow VoIP calls - but they would soon be out of business as users would just switch ISP.

Capitalism will take it's course... countries that block VoIP will suffer economic hardship that outweighs the extra revenue their state telecoms carriers make.

Plus with VoIP encryption it is possible to circumvent VoIP blocking as the status of the packets themselves is disguised. Plus it is possible using simple techniques to overcoming port-blocking:

http://www.hotspotvpn.com/forums/topic.asp?TOPIC_ID=137

But what WILL happen is that telcos will totally revamp their entire networks to move over to IP for voice; data; video etc... Plus local and international cabling will be upgraded to allow very high-speed net connection for movie and video streaming etc...

BT are in the first stage of this with a £10 billion upgrade of part of their system to IP.

And yes - us the consumer will pay for that in the end. And why not?

If you're worried about the huge sums the telcos will make then I suggest you by some shares in them!

Another interesting comment about how VoIP should reduce call costs.

http://www.networkingpipeline.com/blog/archives/2005/10/ebay_ceo_skype.html

Specifically about Skype - but probably valid for other providers in an evolving market.

BUT...realise that these comments ONLY refer to those administrations where there is a strong regulator that supports the consumer. Once again, the 0870 / 0845 NGN scam in the UK will completely distort and negate any possible saving for UK consumers. Indeed, Skype calls that terminate on UK NGN are even more expensive than being placed through other providers.

C'mon Ofcom - we know you read these forums. Get off your backsides; divorce the cosy relationship with your BT Masters; do what you were set up to do and give the British consumer the flexibility and competition that the rest of the western world is enjoying!