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This article, written by Jim Barthold, originally appeared in FatPipe Magazine, 15 April 2005.
The softswitch is dead; long live the …
For a device that is expected to guide the telecommunications industry through its next 100 years of service, the softswitch, and all the components, peripherals and otherwise that make it run, is certainly tough to define.
"The softswitch is really just an industrial strength computer that's a traffic cop and routes streams of data," says John Marsch, founder, chairman of the board and CEO of national reseller TMC Communications.
That might be underselling the device a little bit. After all, the industry continues to talk of a softswitch as a Class 5 replacement, a product that handles all the duties associated with making certain every phone call reaches its destination. Doing the yeoman's work that those big old electromechanical devices have performed so reliably for decades would seem to entail more than turbo charging a computer.
And the softswitch does even more than that, which might make it a "Class 6" switch. But nobody's throwing out that terminology.
"A Class 6 connotation was thrown around by some people years ago with some advanced switches and services even before VoIP," says Chuck Harris, senior director of marketing for softswitch vendor CopperCom. "But it isn't as if switches went through generations one through five and now it's time for six; it was actually based on a hierarchy of switching."
So, while the softswitch is often defined as a Class 5 replacement, "today's voice over IP switches do more than a Class 5 equivalence," says Harris.
Which is precisely why it's not just a switch, notes Rob Scheible, senior marketing manager for Nortel's Carrier Voice over IP (VoIP) business unit. Scheible prefers the term "superclass softswitch" because, in his estimation, it's now a multifunctional device that far surpasses its TDM (time division multiplex) predecessor.
"Maybe the term 'soft' needs to emphasize the fact that the switching is done out at the end device. There probably has to be 40 companies out there that use the term softswitch, and my view is if it's 'soft' it should be flexible and offer all those services," he says.
Those services include switching between VoIP networks; switching between VoIP and the PSTN (public switched telephone network), with the help of media gateways; switching over broadband; and, most recently, a move toward switching over wireless, including roaming in both wireless and wireline networks. Since IP is data, anything that can be packetized can be switched, so this means switching more than voice.
There seems to be some coalescence around a new distributed architecture, the IP Multimedia Subsystem (IMS) that's built off the cell platform and melds many of the principles of cellular switching with the capability to serve as a multimedia model for voice, video and data.
Lucent, which admittedly was slow to enter the softswitch space while defending a large base of installed Class 5 TDM switches, is spearheading the IMS model.
"We don't mention the term softswitch at all," says Mike Cooper, director of convergence solutions for Lucent's Global Marketing & Strategy business group. "We're more focused on multimedia applications, one of which is voice - a very important part of it - but the value to the service provider is not repeating what they did in the Class 4 or Class 5 network but in the value added services in the applications space."
IMS is a distributed soft architecture more than a single device or group of devices. In this architecture, the softswitch has morphed into multiple parts, and data moves out into a common wireless/wireline user profile that can then be used to direct voice, video and data. Call control has evolved into service and session control and, for the time being, the media gateway continues to deliver traffic back and forth from soft to TDM networks.
"The point that's most important is that the applications become much easier to drop into the network," says Cooper.
Although Lucent tries to avoid the term softswitch in the midst of its IMS push, the distributed architecture is "very much a softswitch-based architecture," says Martin Taylor, vice president of technology strategy at softswitch vendor MetaSwitch. "It has call control functions and applications server functions."
These, Martin emphasizes, are all "aspects of the next-generation network that are completely aligned with the softswitch world."
Interestingly, since IMS has evolved from wireless's third-generation partnership program (3GPP), it's an enabler of a quadruple play of services.
"It is a complete end-to-end packet solution for voice over IP with roaming and wireless nets and all the things that the cell phone world brings," Taylor says. "I think it's being seen as a very useful template for the evolution of voice over IP networks."
IMS supports the notion that network access should be agnostic. "It quickly becomes a way for a carrier to now combine all of the wireline and wireless assets as a mechanism to reach the user and then also to layer on top of that all these new multimedia applications," says Dan Dearing, vice president of marketing for session controller vendor NexTone Communications.
NexTone, Dearing believes, will start to play bigger roles in this new IMS paradigm as edge-of-the-network session border controllers evolve into session management devices.
"Session management plays in the core of the network," Dearing says. "You need the ability to traffic engineer your network and control it in the same way a carrier is used to controlling the PSTN network."
Rather than a softswitch, which Dearing dismisses as a "media gateway controller," the session management devices inside the core control the network's functions, he says.
"The routing functionality that people might associate with a softswitch gets subsumed into another platform, which comes out of the IMS architecture and is called the 'call state control' function," he says.
While nearly everyone agrees that IMS carries great promise for the future, it is, in the end, a future generation product. Today's network demands are more in line with moving traditional traffic from Class 4 or 5 TDM switches onto VoIP, if for no other reason than the old TDM gear is wearing out and needs to be replaced.
"To me it's just an evolution of the network, and IMS is how we're tying together the wireless and wireline networks into a single network that deals with all the things that are unique about the wireless network," says Nortel's Scheible.
The immediate concern is the next generation of wireline communications that, in Nortel's vision, will be met by a communications server that is "like a network server, so if you connect into a network today through a data connection or to surf the Web, somewhere along the way there's a server that's serving up the information you're requesting," says Scheible.
That sounds like the model the cable industry's DOCSIS PacketCable Multimedia (PCMM) specs have been evolving toward.
"The (cable) industry sees that voice is, first of all, one of many multimedia applications," says John Falzon, vice president of softswitch and multimedia operations for Telcordia. "PacketCable has realized that a softswitch is really the first multimedia application."
Telcordia, he says, has been helping cable pursue a quadruple play using the wireless MVNO (mobile virtual network operator) concept.
"In conjunction with the softswitch, we have an architecture where we're actually in the process of building a component that will bridge the wireless network and the wireline network," says Falzon. "Obviously, a part of that is the softswitch architecture that manages the IP space."
There's that softswitch again. The industry just can't seem to abandon the term.
The other factor is that the telecommunications space is increasingly fragmented. Cable operators, unburdened by a TDM legacy, are pursuing a strategy that uses their broadband networks. The ILECs (incumbent local exchange carriers) and RBOCs (regional Bell operating companies), saddled with a ton of TDM gear, want migratory paths that keep existing networks in play as long as possible.
It falls to the IOCs (independent operating companies) to be the only pure bastions of softswitch support, opening an opportunity for companies such as CopperCom, which, while keeping a close eye on things such as IMS, is dedicated to building softswitches.
"There's an opportunity there," says CopperCom's Harris.
That opportunity is being subsidized by the federal government's Rural Utilities Services (RUS) that encourages next-generation telecommunications activities among smaller telecom players. CopperCom is RUS-approved.
"For a company like CopperCom to be able to come in and say, 'Listen, maybe it's time to move to the next generation under a model where there is at least some subsidization and support from the government,' makes a lot of sense from a market perspective," says Harris.
It's almost the same as the holding pattern in which the bigger guys are stuck. Instead of pursuing next-gen architectures, the IOCs are putting in Class 5 replacements.
"It really isn't (a Class 5 replacement); it's more," rebuts Harris. "I think it makes it attractive to retire older TDM switching equipment because, while it served well over 20 years, the maintenance costs are getting high, (and) the vendors who sold it are focused maybe on other areas."
It's cheaper than fixing the old or buying a new TDM switch, adds Ed Camarena, senior director of product marketing for softswitch vendor Veraz Networks.
"We've been working with facilities-based service providers, replacing their TDM infrastructure," says Camarena. "They're depending on these solutions as the core of their business. It's really the service provider putting this at the core of how they operate their networks."
Camarena, who acknowledges there will be "a lot of buzz" about IMS, says softswitches are just part of an overall industry movement that happens on an almost regular time schedule as equipment ages, in much the same way the computer industry moved from mainframes to mini-computers to distributed computing and then to tiered layer client-server models.
"You can see that same trend happening in next-generation switching," he says.
And as the trend happens, the way the products interact, and even what they're called, will change as well, perhaps starting with the softswitch, a name that is a "misnomer," says Steve Vogelsang, vice president of marketing for Laurel Networks, which makes routers that interface with VoIP networks.
"The switching isn't really done in the softswitch. It's really more call control and establishing the connection. The actual switching is done in the IP network," he says.
Not only doesn't that solve the softswitch name problem, it creates yet another labeling conundrum. When does it stop being labeled "voice" over IP since voice is only one component of a multimedia offering?
"I can definitely see it within the next few years; it's not far off," Vogelsang says.
VoIP is dead. Long live … FAT
Copyright FatPipe Magazine, 15 April 2005