ICE as a NAT and Firewall traversal mechanism has been around for many years now. In fact, the first draft version of the specification was submitted way back in 2003. Since then, it has undergone multiple revisions and enhancements before it was finally adopted as a standard last year.

The adoption of ICE as a NAT and Firewall Traversal mechanism for the packet applications has gained tremendous interest of late and ICE is now gradually being integrated into more and more packet data applications. This has also been aided by the tremendous growth of the mobile broadband both in terms of the availability and the data capacity.

NAT and Firewall issues are not going to go away any time soon. With the expiration of all available IPv4 addresses and emergence of IPv6, the connectivity scenarios are likely to get more complex. Neither is the transition from IPv4 to IPv6 is going to be smooth and sudden. The networks and devices will slowly and gradually move to IPv6 over a prolonged period. The NAT and Firewall devices are now deeply entrenched in most of the homes, Enterprises, Telecom operator networks, SOHO offices and premises. Add to it the fact that more and more devices are becoming IP enabled and can be remotely monitored and controlled. These devices include IPTV, STB, Home Surveillance Cameras, myriads of clients such as Tablets, Mobile Phones, Laptops and Desktops. Add to it the fact about the availability of the sudden spurt of Internet enabled applications on all these devices. All the applications on all these devices need to support NAT Traversal Mechanism to provide meaningful functionality to the end users.

So far, ICE has been adopted by a number of the standards bodies

• ICE has been adopted by the Cable Labs (consortium of Cable operators) as part of their PacketCable Specifications for delivering advanced, real-time multimedia services. The PacketCable RST and other applications make use of ICE.
• ICE has been adopted by the RTSP 2.0 specification (http://tools.ietf.org/html/draft-ietf-mmusic-rtsp-nat-10) for streaming functionality after a thorough evaluation of all the existing NAT Traversal mechanisms (http://tools.ietf.org/html/draft-ietf-mmusic-rtsp-nat-evaluation-03). The ICE based NAT/Firewall Traversal functionality of RTSP 2.0 protocol makes it a perfect tool for applications such as remote monitoring and surveillance, home automation and security devices.
• ICE can be used with many of the offer-answer based protocols from IETF such as SIP and XMPP.

And is backed by a number of Industry stalwarts

• ICE has been adopted by Microsoft for their Enterprise communication products. Support for ICE is an integral part of their solution for NAT and firewall traversal in the Microsoft Lync server 2010 and Office Communication Server.

Some of the popular applications that currently use ICE are

• Google GTalk client – This XMPP based client uses ICE for NAT and Firewall Traversal.
• Apple FaceTime Application – The popular FaceTime application uses ICE (http://blog.imtc.org/index.php/2010/06/09/the-technology-behind-apples-facetime-standards/).
• Most of the VoIP and multimedia stack/client vendors such as XLite fro Counterpath, SIP/IMS SDKs from Radvision have added support for ICE.

NAT traversal it a bitter pill that can neither be avoided nor ignored. It can be safely assumed and expected that going ahead, more and more packet applications would take care of NAT traversal so that the end users enjoy the functionality of the application irrespective of how and from where their devices are connected to the Internet.

MindBricks ICE SDK provides a comprehensive implementation of the ICE specification for NAT traversal. More information on MindBricks ICE SDK is available at http://www.mindbricks.com/ICE_Lite.html.