Looking to find a way to let peer-to-peer communications traverse NATs and firewalls in a single bound, Microsoft and Cisco Systems recently announced that they are jointly endorsing the Interactive Connectivity Establishment (ICE) methodology.
ICE, which is not yet ratified but currently under consideration by the Internet Engineering Task Force (IETF), is designed to allow people to communicate across NATs and firewall, which can be a barrier to VoIP and other types of rich media communications, according to Russell Bennett, program manager, Real Time Collaboration Group.
“NATs and firewall are prevalent on enterprise networks, at service providers and on home networks,” Bennett said, “They are there for very good reason, but there are side effects.”
Those side effects include either misdirecting or blocking SIP-based VoIP interoperability. “It’s a problem for everyone. There are various classes of NATs and firewalls, but we need to get by them all.”
Bennett noted that proprietary technologies such as Skype get around the problem by disguising VoIP packets are http packets. That approach is “insecure and works only on a small scale,” he said.
ICE is designed to use the STUN (Simple Traversal of UDP through NATs) and TURN (Traversal Using Relay NAT) protocols to allow servers (either at the server provider or on an enterprise network) to work cooperatively to discover, create and verify connectivity. The STUN/TURN servers basically enables a device to ask the servers, “what IP address do you see me as?”, Bennett said.
Why support a methodology that has yet to be ratified by the organization that drafted it? “We don’t know when it will be ratified, but we intended to deploy it anyway. No one has come up with anything and said ‘let’s all get behind this’,” Bennett said. “We are committed to finding ways to allow people to communicate across firewalls. We do intend to ship ICE products. It’s cheap and easy to do. It doesn’t require anyone to buy anything.”