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Unified Communications Magazine May 2008
Volume 1 / Number 6
Unified Communications Magazine
Richard Grigonis

SIP and Unified Communications

SIP, the Session Initiation Protocol – The Session Initiation Protocol (SIP) has become the world’s most important signaling protocol used for nailing up and tearing down multimedia communication sessions (either unicast or multicast) over the Internet and other next-gen networks. (It can additionally be used in any application where session initiation is necessary.) SIP is found in hosted services. SIP dominates the world of IP PBXs and IP phones. Between these two worlds, SIP Peering spurs the growth of revenue-generating services by connecting the “IP islands” of various network operators to support crossnetwork traffic, thus helping to build a larger community of IP users.

By Richard “Zippy” Grigonis

As a 3GPP signaling protocol, SIP is also a principal component of the IP Multimedia Subsystem (IMS) common services architecture and can be used with mobile phones.

Part of SIP’s ubiquity rests on the fact that it is transport-independent and can run over TCP, UDP, or SCTP. Henning Schulzrinne at Columbia University and Mark Handley at UCL started developing SIP in 1996, creating a text-based protocol so that people could actually read and understand its workings. (The latest version of the specification is RFC 3261 from the IETF SIP Working Group.)

Among the latest SIP developments is NeuStar’s SIP-IX service offering, designed to allow service providers take advantage of direct network-to-network interworking of SIP and future IMS-based applications which can deliver value between and among federated communities. Existing IP network peering facilities can be used to originate, terminate and share calls or sessions for mobile, fixed and broadband communications. SIP-IX enables this direct networkto- network peering between carriers for voice, video and content services using SIP-based technologies such as IMS and ENUM (SIP-IX is derived from NeuStar’s commercial private ENUM infrastructure). It integrates NeuStar’s policy-enabled shared directory services into the peering fabric of major Internet Exchange Providers (IXPs) worldwide. NeuStar’s SIP-IX service and Industry Alliance Program assists in performing seamless integration.

Mark Foster, CTO of NeuStar, says, “We were fully involved in developing SIP over the past seven or eight years. Jon Peterson on my staff wrote many SIP RFCs. He co-authored RFC 3261 which actually defines SIP. At the IETF he co-chairs the SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions) working group. So we’ve ‘sat in the driver’s seat’ in developing the core of SIP and a number of key extensions to it, including SIMPLE and SIP Identity to provide end-to-end authentication, and have made efforts in the routing and discovery technology to support SIP, specifically, RFC 3953, which defines the ENUM directory services standard that is the key interoperability technology for accessing our SIP-IX directory.”

“A number of fascinating things have transpired over the last six-to-twelve months,” says Foster. “For example, most people in the communications and carrier space equate SIP with IMS. We’re obviously concerned about the state of IMS adoption in the industry, since there is currently a dearth of applications that have been launched or validated to generate enough revenue to rationalize the huge investment in the IMS core. Our tack at NeuStar is different. What we’re specifically doing in the context of our NGN unit led by Allen Scott is not so much trying to launch entirely new applications and grow them from scratch, but instead look at the profound and immediate benefits of upgrading an existing service. I’m referring here to mobile messaging and the ability to take what is a 10-year-old product, SMS, at $60 billion the second-biggest revenue generator for mobile operators worldwide, and give it shot in the arm in two ways: first, when you replace your mobile phone with one that’s now equipped with this next-generation messaging client, you can now see the presence status of your buddies, so your phonebook becomes your buddy list, which is a profound shift in how users interact with their phone. It now becomes the main user interface for the phone instead of straight dialing. Secondly, you can now initiate person-to-person communications by clicking an icon relative to your buddy’s name. Do you want to send a message? Make a phone call? Make a video call? Send a file?”

“Furthermore, with the ability to now see presence linked with a SIP-based messaging product that is backwards compatible with SMS, this creates an environment where the typical user that upgrades his phone to his next-gen messaging client increases message ‘sends’ by six to eight times,” says Foster. “If you’re a network operator, that’s a recipe to print money. Even if you’re selling by volume, you now have a new capability that dramatically increases the propensity for users to send messages because presence acts as a stimulus for communications behavior. If you see that someone is available, that can remind you that you want to talk to them and stimulates you to give them a call. It’s different than proactively remembering that you need to call somebody and then calling them, seeing that they’re busy and sending a text message instead. There’s a profound shift in how users think about communicating and the propensity to communicate and the stimulus of it, thanks to presence. So we use SIP not to launch a totally new service, but on what’s being positioned and targeted as SMS 2.0, SMS-plus or SMS turbo, if you will.”

“This approach both generates new revenue from the user and yet the cost of implementing this IP-based messaging product is one-third on a per message basis, than investing in additional capacity for text messaging,” says Foster. “Since text messaging use continues to grow, carriers are spending lots of money to expand their infrastructure. So there are huge cost savings and it’s a loyalty and ARPU enhancer, all in the context of taking a legacy service and upgrading it to one with SIP-based capability. We think this is an exciting and pragmatic strategy for how to facilitate the evolution of existing mobile and fixed networks from their legacy, circuit-switched SS7 environments to SIP, as opposed to traditional wisdom which is to invest in a huge IMS core and build new applications that may attract users. SIP is thus on-track to becoming the technology answer behind upgrading core capabilities in mainsteam use today.”

“The second big development was an announcement we made in February 2008,” says Foster. “Our SIP-IX suite of services provides IP directory services for private carrier ENUM services and all of the numbering management provisioning directory capabilities associated with that. We’ve been selling that product in several forms for the past four years. In fact, most of our customers for this product have been mobile operators, who use it for mobile messaging and some VoIP. Recently we announced the franchise sale of SIP-IX to the global wireless industry through a contract with the GSM Association (GSMA). We’re under contract with them to provide a common, shared, private carrier ENUM directory service on behalf of all 700 GSM operators worldwide, serving 3 billion subscribers. And in fact it involves all mobile operators and all carriers, fixed, Internet, content providers and ecommerce providers who interact with and are part of the mobile ecosystem, which is pretty much everybody.”

“This is not just exciting for NeuStar, but is a milestone in the evolution of the industry,” says Foster. “This is the ‘big bang’ of IP interconnectivity and interoperability. This now provides a common shared ENUM directory service that can be used to enable interworking amongst mobile operators and their trading partners for the exchange of everything from voice traffic to migration of text messaging from SS7 to IP, to also enabling the interoperability of more embryonic, next-generation services such as IM, presence, video telephony, push-to-talk over cellular, content services and even mobile money transfer applications. The ability to access a common IP directory, which includes, by the way, number portability data for 45 countries around the world, is something we believe to be a revolutionary milestone forward to facilitate the wide-scale adoption of IP-based and SIP-based services.”

“The two areas that excite the industry most are, not surprisingly, the cost savings in virtualizing the way the mobile operators interconnect today,” says Foster, “moving away from circuit-switched, point-to-point connections as they typically do for voice or SS7, and moving toward using the existing IP interconnect facilities that are already used today for Internet peering. It’s the ability to use that same interconnect infrastructure on a private basis for exchanging services such as voice messaging and other next-gen services. This unlocks huge value for the carrier space in particular, for broad-scale adoption of SIP services, likely starting at the intercarrier/ interconnect layer, and this will catalyze adoption of SIP further down into the interior of the mobile networks.”

One Device, One Pipe

U4EA Technologies Fusion Series of multi-service business gateways, U4EA Technologies is a leading provider of multi-service business gateways that enable service providers to deploy highly integrated IP communications solutions to SMB and enterprise customers. U4EA’s all-in-one customer premises devices are controlled by proprietary QoS (GoS) mechanisms that ensure the delivery of converged VoIP, data and video services. The U4EA Fusion Series also includes next generation network signaling gateways, enabling carriers to interconnect legacy networks and equipment with next-gen networks.

Jim Greenway, Vice President of Products and Marketing at U4EA, says, “I separate UC into two aspects, because people are confused by UC. Unified communications has been talked about for quite a while from the perspective of unified messaging and telephony-enabling desktop and laptop applications, which involves unifying voicemail, email, IM, text messaging, and so forth. This type of UC application exists mainly on the desktop and people are talking about things such as Microsoft’s OCS and Nortel OCS which telephony enable applications. That’s one definition of unified communications — the desktop or laptop-specific form of it. The second definition of UC is used by the VoIP industry and that’s ‘Network UC’. Some analysts don’t even cover this area. We’re focused on the premise-to-network piece of UC. I do believe that SIP is both fundamental and instrumental to all this. I jokingly call it, ‘the chosen protocol’. It’s certainly the principal protocol for VoIP.”

“SIP plays an important role in IMS and FMC too,” says Greenway. “If IMS ever takes over the world as a common service architecture for wireless and wireline communications, certainly SIP will still be the backbone protocol of that. We talk about getting communications from the facilities and employees of everything ranging from SMBs to the largest enterprises and network service providers – that’s where we’re focused in terms of unified communications. And I do really think that SIP is an important piece of that landscape.”

“Now let me focus more on ‘Network UC’ versus what you’d call ‘Desktop UC’ or ‘Laptop UC’ or ‘Application UC’,” says Greenway. “Ironically, the desktop versions of UC eventually have to make their way to the network. We’re actually working on the transport issues to ensure that UC does travel from the desktop to the network. More of that to come. As to what we’re currently doing with UC from a premise-to-network perspective, if you look at service providers touting that they provide UC, when you break it down, you discover that there are several pieces to the puzzle. First there’s ‘data Internet service’ obviously to an ISP of some sort; then there’s ‘voice or VoIP services’ which itself breaks up into ‘hosted IP’, ‘IP trunking’ and ‘legacy PBX-to-IP conversion’. The final area involves putting an umbrella over everything under the rubric of managed network services.”

“What’s interesting about U4EA’s technology is that we are developing devices that sit, typically, at the edge of premise networks,” says Greenway. “Again, it can be a small business totally served by hosted services or else a very large enterprise. We allow all of these services to flow through our gateway device. With Network UC you must be able to combine and handle all of the prerequisite media, which includes voice, data, video, collaboration, perhaps even a bit of IPTV, though we view that mostly as a residential service. Essentially, Network UC involves taking all of these forms of communication that a business requires and ultimately running it through a single edge device over a single network access pipe, which is an IP pipe that goes back to an ISP, and many SIP-based services are carried through that.”

“We’re seeing a predominant amount of VoIP traffic which is SIP-based,” says Greenway. “Data comes in a variety of forms, transported mostly by TCP/IP, obviously, and we’re seeing some interesting combinations. There’s also streaming video, which is IP and even SIP-based. A third area of SIP influence is something relatively new called SIP Trunking. SIP trunks enable you and your business to use your IP PBX phones over an Internet connection.”

“We talk to dozens of companies, providers and big carriers such as BT,” says Greenway. “Ultimately they’re all moving to an IP backbone infrastructure, but it has taken longer than I think any of us in the industry had thought it would, because it tends to be a major change for many of these people. I believe Network UC is happening and will continue to evolve, primarily because there are costs savings. Some service providers are touting SIP trunking by saying, ‘Hey, if you use SIP for everything, we can take care of your communications with fewer SIP trunks and ‘channels’ if you will, than you would with an ISDN Primary Rate Interface, and we’ll cut your costs by a third to one-half. That’s where SIP is making another huge impact, following its initial impact in the world of IP PBXs. H.343 and MGCP started out to be leading protocols in hosted VoIP from service providers. But that field has swung over to using SIP too. So all three areas of major communications activity – IP PBXs, hosted voice and SIP trunking – are standardizing on SIP.”

“We get everything to travel down one pipe.” says Greenway. “Our devices attach to this and provide routing, switching, VoIP, security, SIP trunking, DNS, DHCP, and all of the things that a small business or a corporation would typically take care of with many separate devices. We can do it all with one device and one data stream, and that stream is typically one of three types: an Ethernet interface into a router, a T1/ E1 interface directly into a service providers network, or it’s a DSL connection, be it ADSL+, ADSL2+ or now VDSL. Our products deploy the same software to combine all of this voice, data and video information into a single pipe and the variations are now occurring more in the pipe. The telcos using DSL are battling with the cablecos. And there are cable modems which can accept Ethernet. So that’s a very interesting environment. In any case, we’re like arms dealers, we don’t care what the network interface is. We can give you support for ADSL, T1/E1 or Ethernet connections, it’s your choice. Our key ‘secret sauce’ is to combine all of this stuff through a single device that can be delivered down the single pipe.”

“Other, very large vendors are on the same path as U4EA,” says Greenway, “but our key differentiator is our QoS [Quality of Service]. As customers try to do more with less and cram more traffic down a single pipe, we’ve come up with a way so that we can literally guarantee that, over that single pipe, you can utilize 90 percent of the available bandwidth. We can prioritize and rearrange traffic according to the way you want it done, versus some other methods such as Low Latency Queuing [LLQ] the literature of which warns you not to load the link more than about 33 percent to guarantee quality. No doubt, our method of QoS is the best in the market.”

SIP’s progress has been tremendous and its adoption rate won’t decline any time soon. If you look around on your desk or nearby, you’ll probably find a “SIP device” of some sort, waiting for you to use it.

Richard Grigonis is Executive Editor of TMC’s IP Communications Group.

Unified Communications Communications Magazine Table of Contents

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