VoIP Peering

• ISN: "An ISN is formed by joining a domain-local subscriber number to an ITAD (Internet Telephony Administrative Domain) number, using an asterisk as the delimiter. For example, subscriber 1234 in ITAD 256 would have ISN: 1234*256." overview
• IPeerX
• FiberNet
• GSMA
• Xconnect
• VPF