Much has been written in recent months about Session Initiation Protocol, otherwise known as SIP. SIP has helped grow the VoIP industry and made it possible to introduce many new and useful applications.

 

TMCnet.com recently spoke with Michael Hartley, spokesperson for AGN VoIP, about why SIP appears to have won out as the de facto industry standard in VoIP protocols.  

 

 

Hartley said there are three main reasons why SIP—which he said was developed at Columbia University and first entered the VoIP scene in September 1999—is being so widely adopted as the industry standard in VoIP protocols.

 

1. SIP is a much simpler protocol than its prior competitors.

 

2. SIP is portable. It can be enabled on plain old telephones, cellphone, IM clients, and even TV sets.

 

3. SIP is riding the momentum of its widespread adoption; as more people choose to go with SIP, it becomes even more solidly accepted as the VoIP protocol.

 

 

Hartley said there aren’t really any true competitors with SIP when it comes to VoIP standards. He listed the following protocols as being, for all intents and purposes, former rivals of SIP.

 

1. H.323, the protocol used for NetMeeting.

 

2. Inter Asterisk Exchange (IAX), native to Asterisk’s  PBX.

 

3. MCGP.

 

 

According to Hartley, the biggest threat to SIP is probably proprietary VoIP protocols. Protocols that work only with certain applications or hardware are the antithesis of the utopian VoIP dream: a new communications technology that will do away with the need for phone companies.

 

Hartley said that the VoIP dream is still a long way off. But, an encouraging sign is the fact that, at the enterprise level, established VoIP companies such as Avaya and Nortel are transitioning toward SIP.

 

Another threat to SIP, Hartley noted, is the development of proprietary versions of SIP itself. (That is, protocols modify the SIP base so that it no longer complies with industry standards.) Proprietary versions of SIP are developed to add functionality to SIP, but at a cost to compatibility.

 

 

Of course, no discussion about SIP would be complete without mentioning security. But, Hartley said this is only a perceived threat to SIP.

 

“To my knowledge there have not been any significant SIP vulnerabilities,” Hartley told TMCnet.

 

Hartley acknowledged that firewalls have created difficulties for SIP-based applications in the past, but the problem will soon be a thing of the past. A whole industry is cropping up of firewall developers who are making their products SIP-aware.

 

Established companies such as Cisco and Juniper are beginning to address the problem, too.

 

“It's just a matter of time,” Hartley told TMCnet.