Implementing VOIP in a network/domain -
Telia is expected to light up its American fiber this year. Continuing discussion of the emergence of competing network 'visions' aggregated on fiber backbone, and the integration of the Mobile Last Mile into such domains, the following:
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Telia first for SIP-enabled phone services
By Roy Rubenstein
17 July 2000
Several global telecoms operators are rolling out a technology to enable a new generation of corporate services based on the telephone.
The operators, including Telia AB, Level 3 Communications Inc. and Aduronet Ltd., are adopting the session initiation protocol (SIP) within their networks, while a major European telecoms operator is creating a separate company to offer SIP-enabled services.
Sweden's Telia is implementing SIP within its internal networks. In a full-scale demonstration of how services can be delivered to the corporate user environment, all of its 27,000 staff have been issued with a SIP "identifier," allowing them to be called on the phone through their electronic mail addresses.
"This is very significant," said Iain Stevenson, analyst at Ovum Ltd., of London. "[For the first time] an established carrier is confident enough to release [SIP] for large[-scale] use."
SIP is a general purpose signaling scheme for establishing communications between two or more Internet devices. It also promises to turn telephone sets into intelligent edge-of-network devices in corporate networks, capable of anything from delivering a user's desktop phone communications service wherever they go, to ringing through alerts designed to aid life management processes.
The public endorsement of SIP by Telia is also a feather in the cap for the Internet Engineering Task Force, the standards body behind SIP, as it enters a market already using the more established, ITU-backed H.323 standard (see story below).
Telia's staff now have a multi-purpose identifier which, through the use of a Telia gateway, not only enables them to receive voice and e-mail but video transmissions and conference calls, all through one SIP address.
"It's a great demonstrator of the future," said Jeff Pulver of New York-based Pulver.com, and organizer of last month's Stockholm-based Voice on the Net conference, where Telia first disclosed it had implemented SIP. "For me [what is significant] is that a service provider has put this into commercial operation," said Pulver.
Another major European operator, meanwhile, is backing a new company that will deliver SIP-enabled services. "SIP will allow toll-free and advanced call services to move from fixed to IP networks," said an industry source who did not want to be named. "It offers a huge opportunity" for cost savings over medium- and long-haul links due to the compression ratio advantages of voice over Internet Protocol, he said.
Operators WorldCom Inc. and Aduronet are also studying SIP-based services.
"In terms of market momentum, SIP has got it," said David Bauhs, director of product marketing at Dynamicsoft Inc., a SIP specialist start-up based in East Hanover, New Jersey.
This includes the selection of SIP by the Third Generation Partnership Project (3GPP) group as the signaling protocol for voice in 3G mobile networks and handsets.
"UMTS is going in the direction of IP," said Dominique Delisle, IP program director at France Telecom SA's research and develop center in Paris. "And for the control of the telephony it is [adopting] SIP rather than H.323."
Telia, Dynamicsoft and WorldCom all claim SIP has significant benefits over what they perceive as the complex H.323. "[SIP] is a lightweight protocol which is very easy to use to make applications with," said Mattias Lignell, senior adviser, technology, at Telia.
However, not everyone agrees.
"It's a marketing thing - the IETF is perceived to be modern," said Helmut Schink, Siemens AG's head of department for Internet standards and chair of the project Tiphon, part of the European Telecommunications Standards Institute's global standards work for interoperability between IP and circuit-switched networks. For Schink, SIP is an alternative solution with more or less the same features as H.323. "SIP is perceived as simpler but it is now becoming of the same complexity [as H.323]," he said.
According to Dr. Henry Sinnreich, distinguished member, multimedia services engineering, WorldCom, the two are completely different. H.323 comes from the circuit-switched world, running over local area networks, while SIP is designed for the Net. "[SIP] is completely distributed with no central control."
Telia's adoption of SIP is part of its planned voice-over-IP service to its broadband customers; Sweden is providing broadband access to all of its 4 million households.
The operator admits that the immediate benefit of its staff adopting SIP numbers is limited. After all, most have mobile handsets rather than SIP phones. "It is more to get the ball rolling," said Lignell.
Lignell highlights how he already uses his handheld Palm Pilot to pass his profile detail to an IP telephone when he visits off-site locations.
This is sent to the local proxy server, which then gets in touch with his home proxy server. The result is that calls get routed to him.
Other operators say SIP will be the basis of revenue-generating new unified IP applications built on voice communications.
"Services is the only way to get new revenues," said WorldCom's Sinnreich.
He highlighted such SIP-enabled call features as locating the person being called (office or home), their call state (ready or on another call), whether the recipient is willing to receive a call and from whom, and their preferred medium for communication: text, voice, video, or e-mail.
And Aduronet of London is working with Dynamicsoft to use SIP as a mechanism to enable advanced services to run on its new network.
Users' expectation is such that they want to be able to access the same services whether they are using a PC or a mobile device. "The engine to generate the linkage has to be in the network," said Brian Levy, Aduronet's senior vice president of technology, and this is where SIP comes in.
Ultimately he sees SIP as a way of linking voice and the Internet. "We see an opportunity to close the gap between the Internet and voice networks in a way that has not been there before."
Running voice applications from voice application service providers and telecoms carriers on its VoIP networks is also what is motivating Level 3's adoption of SIP in its softswitches.
Meanwhile, Pingtel Corp., of Woburn, Massachusetts, is developing a SIP phone called PINGTEL to appear on the market in the third quarter. It features a Java virtual machine that executes downloaded software applications, and a screen comparable to that of a Palm Pilot. "The phone becomes an application platform," said Jay Batson, chief executive of Pingtel.
Batson said one customer wrote an application in a hour for the phone to notify him to have a banana and a glass of water at 3pm each day.
SIP and H.323: The pros and cons
Both the H.323 and SIP voice-over-the-Internet protocols set up and tear down basic calls. The two support the real-time protocol, use network servers - gateway proxies - for routing, and cater for multimedia content.
The ITU-inspired H.323 is an older standard developed originally for LAN videoconferencing. As such it includes several protocol components that require management even for simple calls, accounting for H.323's reputation for complexity. "H.323 has been the starting point for a lot of people but it has encountered scaling problems which has caused carriers to rethink and look at SIP," said Carl Ford, Pulver.com.
In contrast, Telia and other operators describe SIP as simple, open and extendible. "As a call enabler with a language sitting over the top, [SIP] goes way beyond what H.323 has to offer," said one industry source.
According to Fred Baker, chair of the IETF, both standards get used, but he believes that a better set of guidelines were chosen for SIP that were "more in keeping with Internet technology."
SIP's recent uptake is largely due to its "Internetish approach to voice over IP," added Jonathan Rosenberg, one of the co-developers of SIP and chief scientist at Dynamicsoft.
"SIP is very similar to html," said R.J. Mahadev, vice president of global softswitch services at Level 3. "It promises to make creating voice applications as straightforward as it is to write Web pages."
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