Dean Elwood over at VoIPUser.org put up a post yesterday entitled "How to Build a VoIP Network" in which he goes into precisely what is needed to set yourself up as a VoIP Service Provider (or "Internet Telephony Service Provider" (ISTP)). Given that Dean's been involved with this through VoIPuser.org, he's definitely got some credibility. As he says, he wrote the piece because:
We see a lot of threads on VoIP User from people who want to be the next Niklas Zennstrom (and fair enough, we hope you succeed) asking what is required to build a VoIP network.
Often these questions are from users who have a basic technical understanding of how it all works, but no real experience of building networks, or telcoms experience with the good old PSTN.
He goes on to offer these seven rules:
1. if you're a marketing genius, you have a greater chance of success with your new VoIP company than if you are a technical genius.
2. Using the internet to route calls does not mean that everything in the VoIP world runs on Intel *nix.
3. It is going to break at some point. Ensure you have redundancy.
4. The transition from voice 1.0 to voice 2.0 will be managed at the cloud edge.
5. Network considerations made at design stage must include Quality of Service, audio path length and NAT traversal
6. Choose your hosting according to needs of each individual server, not the entire network. A Layer 5 network, such as a SIP network, can be distributed geographically.
7. Don't bet the house on it.
You really need to read the full article to understand Dean's rules and also enjoy his wit. For those seriously interested, he goes into what the costs would be to get set up. (I'd tell you, but it's best to read Dean's article for the context.)
Now, there are certainly other costs, as Dean indicates, but the net of it is that it really isn't all that much for someone to get into business. The ease and low cost is bringing a whole host of new entrants... most of whom, on a side note, are not thinking about security as they rush to market (leading to my repeated prediction over on Blue Box that it is only a matter of time until one of them gets hacked).
Anyway, it's good info and definitely worth a read.