Is Nat Traversal holding back VoIP and IP Communications adoption?

Voice over Internet Protocol (VoIP) communications is quickly becoming an integral part of the consumer and business markets. High quality multimedia communications along with rich presence, universal mobility and availability, and lower cost are some of the benefits VoIP brings to end-users. For operators, it promises new revenues from new and converged services, service bundling, increased customer loyalty, and lower capital and operation expenses by building and running a single IP-based network for all communications services.

The increased penetration of broadband Internet, the main driving force behind VoIP adoption, also poses one of the biggest challenges – VoIP calls do not work well in many broadband situations for NATs and Firewalls break VoIP.
To address my concerns about NAT Traversal and the future of VoIP I had the CTO of Eyeball Networks, a leading software provider for VoIP, video telephony and instant messaging, answer a few questions.

What is NAT, and why should I be concerned about NAT traversal?

More than 90 percent of PCs or end-devices access the broadband Internet using private IP addresses. These private IP addresses get mapped into real Internet addresses using a mechanism called Network Address Translation (NAT), which is implemented in all broadband access devices (also called broadband routers such as from LinkSys, NetGear or SMC) and sometimes also in the service provider network.

NAT traversal refers to the problem, and solution thereof, where two computers behind NATs sometimes fail to communicate with each other for features such as IM, VoIP, file-sharing and online-games. If you are building devices, applications or services involving Internet communications, then NAT traversal should be a concern.

What are some applications NAT traversal technology is used for?

A list of applications requiring NAT traversal technologies follow:
• VoIP and video telephony
• File-sharing such as picture and video sharing
• Online games
• Collaboration tools such as presentation and white-boarding
• Any other applications using client-to-client data transfer

How has the availability of effective NAT traversal solutions changed the way VoIP and other IP-based services are delivered and used?

Traditionally NAT traversal has been one of the critical barriers for widespread VoIP adoption. Development of IETF standards such as STUN, TURN and ICE provide a rich set of mechanisms for an interoperable standards-based and scalable solution to this problem. Availability of an effective NAT traversal solution such as Eyeball AnyFirewall Engine has removed this barrier providing guaranteed traversal of VoIP calls through NATs, firewalls and web-proxies. It is effectively bringing VoIP and other IP-based services to plug and play level between devices, applications and service providers.

What are some of the challenges traditionally faced by developers of client-to-client networking applications, especially in peer-to-peer and VoIP settings?

Traditionally developers did not have proper technologies and tools to solve the NAT traversal problem for client-to-client networking applications. For example, for VoIP applications the developers/operators faced the following issues.

Some products implemented only partial NAT traversal solution. For example, many VoIP phones only support STUN, and therefore cannot be used for client-to-client data transfer by most broadband Internet users.

In most cases, operators settled for using a relay server (such as Session Border Controller) for all calls. Since all calls are relayed, the relay server becomes a bottleneck (and expensive) for service scalability, and deteriorates call quality by injecting additional delay, jitter and packet-loss. Also since SBCs implement proprietary protocols products from one vendor do not work with those from another vendor.

In some cases, developers have developed proprietary NAT traversal solutions (such as Skype) that do not interoperate with others.

What types of features and capabilities is the VoIP industry looking for in a NAT traversal solution?

Here is a list if features and capabilities the VoIP industry is looking for:
• 100 percent traversal of VoIP calls through NATs, firewalls and web-proxies.
• Standard-based solution to ensure 3rd party interoperability (IETF drafts STUN, TURN and ICE).
• Works without changing NATs, firewalls or other infrastructures.
• Most calls should be peer-to-peer for best media quality and scalability.
• Comprehensive solution with handset/client and server components.
• Small footprint for the end-point solution with support for multiple PC and embedded platforms.
• Mature and field-proven technology.
• The bottom-line is that when a user purchases a VoIP phone or service, it should just work in all cases without any service scalability bottlenecks.

What is AnyFirewall Technology and how is it being used by companies in the VoIP industry?

The award winning AnyFirewall™ Engine is the industry's leading NAT traversal Software Development Kit (SDK) for guaranteed VoIP and video call completion across NATs, firewalls, and Web proxies. AFE incorporates the most -- comprehensive implementation of the IETF standards STUN, TURN and ICE. Eyeball's patented AnyFirewall™ Technology offers - for the first time in the industry- a completely software-based solution that is standards-based (i.e. STUN, TURN, ICE) and primarily peer-to-peer resulting in 100% VoIP and video call completion. Our customers are integrating this technology into soft phones, video phones, set-top boxes, and PDA-based mobile phones.

Why use STUN, TURN and ICE for NAT traversal technologies?

STUN, TURN and ICE are results of international standardization body IETF which is responsible for developing all Internet-related protocols. Together they provide an excellent methodology for NAT traversal which is being standardized in order to ensure interoperability between products and services from different vendors. Earlier efforts on NAT traversal solutions such as application level gateways (ALGs) and session border controllers (SBCs) either did not work well enough or had interoperability, performance and scalability problems. STUN, TURN and ICE have received widespread industry support from vendors such as Cisco, Microsoft and Nokia; and has been adopted for CableLabs IMS specification for next-generation communications architecture. Eyeball AnyFirewall Engine provides the most comprehensive implementation of STUN, TURN and ICE along with features such as UPnP and http-tunneling.

In a nut shell I found that NAT devices and firewalls are major barriers to the widespread adoption of VoIP, and IETF work STUN, TURN, and ICE provide an excellent methodology to address this issue. However, implementation of these methodologies requires considerable insight and experience. Eyeball Networks has invested many years to develop its AnyFirewall technology, the most comprehensive implementation of STUN TURN and ICE, to enable service providers and device makers software to ensure 100% firewall and NAT traversal of IP communications. If VoIP providers and device makers take advantage of this AnyFirewall Technology Nat Traversal will no longer be a concern, and IP communications will one day overtake the usage of traditional phone lines.

By Brian Ellis BSc
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For more information on Eyeball Networks visit www.nattraversal.com
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