The Great Leap Forward

Want to make venture capitalists swoon? Say "e-commerce." Want to make wireless carriers swoon? Say "IP." Both camps are swooning at the possibility of grabbing huge competitive leads by cutting costsand upending traditional business models.

With IP, the appeal is shared bandwidth, which translates into greater efficiency and lower costs. For most wireless carriers, their evolution will begin by routing signaling traffic over IP.

"It's more of a data-oriented activity and therefore very conducive to packetization," said Jesse Russell, AT&T Labs advanced communications technology vice president.

One concern is what amounts to a culture clash between SS7 and IP. Carriers want IP's efficiency, but they don't want to give up SS7's reliability and quality-of-service (QoS) guarantees. Overprovisioning, the norm with SS7, also could work for an IP network.

"When you do, you still get the bandwidth efficiency and cost savings because of the technology," said Ravi Ravishankar, Tekelec director of converging technologies. "There's nothing to prevent a carrier from over-engineering an IP network."

Overprovisioning alone might not be enough. IP makes it easier and cheaper to deploy enhanced services, but if those services suddenly become wildly popular, the surge in traffic could strain the network. Careful forecasting could help ensure that the IP network can accommodate usage demands.

"Under normal conditions, you might be using only half of that bandwidth," said Dave Cox, Tekelec network-switching division director of product marketing. "But at peak times, it might go up and be more than the pipe can handle. So there are more network grade-of-service characteristics that you need to be aware of. Not to say it's bad or not doable. It just (requires) a little more planning."

LIVING UP TO TELCO STANDARDSAn IP network can be either public, like the Internet, or private, like an intranet. The more direct control over that network, the more it can be tweaked to provide telco-quality service.

"In the short term, I don't see doing IP signaling over the Internet," said Joe Hannon, US West Wireless director of network engineering/PCS. "For a long time, this will be a private IP network that we'll build, but one that we can do a lot more with."

The Internet Engineering Task Force (IETF) is working on solutions such as differentiated services, where each packet would bear a "label" identifying its QoS requirements. That should help expand IP beyond a vehicle just for signaling.

"The voice traffic or other delay-sensitive traffic would get a fast lane through the switch, kind of like an express lane on the highway for car-pooling, whereas the other traffic goes through the regular path through the switch that may have more delay," said David Smith, Nortel Networks director of wireless Internet product management.

Prioritization is important because IP makes it easy to interconnect computer and telephony networks. Downloading a huge file over a common IP network shouldn't bog down call completion.

"The way that routers and routed switches are evolving, the information in the packet that has the priority and address is understood when (it) hits the switch so that it's routed into the appropriate queue," Smith said. "You shouldn't have to add any additional buffering or anything new to address any weirdness in the network."

Another hurdle is overcoming IP's reputation as prone to delay and thus ill suited for telephony applications, especially wireless. After all, IP was designed to operate in a circuit-switched environment with stationary users.

"Both IP and ATM core network products have been designed to address all of these delay and latency issues," Smith said. "It's no longer the case where an IP router is actually just a computer that's doing everything in software. It's now a highly optimized, hardware-based device that can route packets through either a very fast path or a path that has more latency and delay. So I think that with the advances in IP routers and IP switches, you can actually address the delay characteristics of wireless even over an IP network."

IN WITH THE NEWIP's ability to streamline interconnection between computer and telephony networks is an asset even if the infamous wireless-data boom never materializes. With an SS7/IP gateway, a carrier could leverage the investment and reliability of the existing SS7 infrastructure but still deploy new enhanced services on the IP network. The IP world's open standards make it easier and cheaper to develop services because they don't require proprietary telco hardware and software.

"These industry-standard servers are going to displace what I call the big proprietary refrigerators," said Arno Schmidt, Nortel Networks vice president of wireless Internet marketing. "We've actually taken the bold step of saying that we'll reuse our MSCs initially as servers, but ultimately, we think that even our MSCs are going to go away, and they're going to become one of the servers attached to this open-services architecture."

The difficulty of migrating to IP depends partly on the existing network and the effect on legacy systems. For example, if the signal-transfer-point (STP) vendor approaches IP as just another protocol stack, upgrading might be as simple as plugging in a card that provides the IP interface.

"Our initial interface is going to be from the HLR to the STPs," said Hannon of US West Wireless, which uses Tekelec's IP7 SS7/IP gateways. "The next thing to go IP will be the C links between the STP pairs that we're deploying. So we'll have that totally on an IP backbone. Then we'll have the ability to move some of our B links (to IP). I'm talking to SS7 transport providers about the possibility of them putting this Tekelec (IP interface) card in their STPs, and we hook up to them (via) IP. That's probably sometime next year. We're trying to get everything that's in the IN domain into the IP domain."

One drawback to linking IN and IP is that each interconnection point is a potential back door for hackers. Limiting the number of points is one solution. For example, instead of having SS7 protocol stacks in each IP device, Tekelec's IP7 sits at a high point in the network and serves as a gateway for the IP devices below it.

"The fewer points of interconnection you have, the easier it is to control the security and the less likelihood of breaches," said Tekelec's Cox. "If you had a hundred of those in your network, that's a hundred points of interconnection. It's a lot easier to put in one gateway that might control 50 or 100 boxes and have the security at that one box."

Additional layers of security include screening and firewalls in the SS7/IP gateway, authentication, encryption and tunneling, which provides a secure route across the IP network.

"What you're doing is taking all your traffic, which is packets, and kind of sticking them all in brown-paper envelopes with just a header address (for the) remote location," said Nortel's Smith. "There's been a huge amount of work done in encrypting both access data and the network. We believe that it's been used for so many things (such as) banking transactions that it is ready for prime time."