Dawn of a New Error

When the first new telephone exchange arrived in Southampton, NY, in the late 1980s, homebuyers in this tony village on Long Island's East End often negotiated to keep the seller's phone number. The reason: It identified them as old money.

Today, thanks to LNP, they can port them to Palm Springs, CA, or Carmel, CA, although most probably aren't aware of their new freedom. The dearth of advertising emphasizing LNP suggests that LECs and CLECs aren't yet comfortable with the LNP process. Even so, more wireline numbers were ported in the first four months of 1999 than in all of 1998, and the total likely will double to more than 2 million by year-end.

What that means for wireless is that many LNP headaches didn't disappear when the FCC postponed wireless LNP. Two million might sound insignificant, but if just one number in an NPA-NXX ports, calls to the remaining 9,999 numbers also require an LNP-database lookup, called a "dip." If that isn't enough cause for concern, remember that roughly 70% of wireless calls terminate to a wireline number. Even if you subtract long-distance calls, where the dip is the responsibility of the IXC, most carriers will see the number of dips grow significantly.

"I estimate that upward of 50% of the (non-long-distance) calls that come out of our networks will require queries by the end of the year," said Chris Kostenbader, Bell Atlantic Mobile (BAM) director of network switch and facilities planning. "That's still a lot of calls."

Most carriers either outsource LNP to a service provider, such as Illuminet, or default to the LEC, which typically charges between $0.00022 to $0.004662 per dip. Like most carriers, BAM is implementing an in-house LNP solution not just to reduce costs but to get more control over quality of service (QoS). Defaulting to the LEC means flying blind: If the LEC doesn't complete the call correctly or in a timely manner, the wireless carrier won't know because it doesn't have visibility into the LEC's network.

"Right now, the only way that we're doing it is, unfortunately, through customer complaints because we're relying on the LEC to do the queries for us," Kostenbader said. "We're putting our faith in them."

Problem is, it's BAM, not Bell Atlantic, that is the public face of LNP to its subscribers. The affiliation doesn't necessarily offer many advantages, either. For one, wireless' IS-41 and wireline's advanced IN aren't 100% compatible, so BAM can't simply tap Bell Atlantic's LNP database. For another, regulators wouldn't allow a LEC to offer its wireless affiliate any services that a competing wireless carrier couldn't also buy. Even so, being a LEC affiliate can help track down problems.

"If the provider 'owns' both the wireless and wireline networks, then a definitive answer can be found whether or not the call is completed correctly," said Dan Bantukul, Tekelec IN Diagnostics division senior manager of product marketing. "This is because it has visibility into both networks. For the provider that doesn't own both networks, they still can (determine) whether the call is completed or not but not definitively: The call can be traced only up to the gateway between the networks."

FAULT & DEFAULTFor carriers without an affiliation with an LEC or an in-house LNP solution, the picture is even gloomier. Subscriber complaints often are the only way to determine whether calls to ported numbers are completed correctly.

"The wireless provider can monitor calls entering the wireline network and monitor the responses from the wireline network," Bantukul said. "The responses will tell the wireless provider if the call has been completed or not. The only problem with this type of tracing is that the wireless provider can't tell if the call is completed to the correct ported number."

Other clues can be gleaned by using tools such as Inet's GeoProbe or Tekelec's INsight7 to compare switch data to the bills from the LEC or service bureau. If the bill shows 5 million LNP queries last month, and the switch says it sent only 3 million, then something is amiss. Bill reconciliation also helps avoid charges for LNP queries never made.

"They can ask the LEC to provide them with a report that tells exactly how many calls on the interconnect links (and) how many call attempts were made, minutes of use (and), for LNP calls, if the dip was made, was it made successfully (and) if there were any time outs," said Samir Marwaha, Inet OSS marketing-strategy manager.

Such historical information often doesn't provide enough clues to track down the reason why, for example, a call to a ported number doesn't always complete.

"We've heard from CLECs that there have been situations in which -- and we have not been able to verify this -- our wireless customers have experienced difficulty in reaching ported wireline numbers," said John Woodward, GTE Wireless technology-programs director, which is bringing LNP in house. "We're happy to cooperate with the CLECs in trying to chase down these situations. But right now, we don't have enough information to go on."

KNOWLEDGE IS POWERAn in-house LNP solution allows network-management tools to monitor statistics such as the ratio of successful call releases to call attempts.

"They can also monitor any call failures due to LNP problems by simply typing in the problem telephone number and capturing every message associated with the call," said Garry Avery, Hewlett-Packard acceSS7 surveillance solutions product-marketing manager.

An ideal LNP-monitoring solution also includes the ability to monitor the performance of the LNP system itself.

"You'd want to have visibility into system performance (such as) processor occupancy and response rates," said Kevin Cavanaugh, ADC software-systems division director of product research. "Time out is potentially an issue in terms of latency performing the look-up."

Even with the latest and greatest monitoring tools, troubleshooting still can be difficult because the source of a problem could lie outside the wireless network. New area codes and overlays only add to the confusion.

"If it's a new exchange, for example, then you can also have switch-translation problems, which can cause a bottleneck," Cavanaugh said. "Then the question is, do you own that switch? Does the LEC own it? So there are a number of parties involved. If it's a particular exchange, you can trace through the signaling process in the message."

Another concern is the burden on the SS7 network, where bottlenecks can occur if it can't handle the additional messages as the number of dips increases. Deploying a robust LNP solution with end-to-end monitoring also can ease migration to number pooling, which builds on LNP.

"The performance between the NPAC and the local service-management system (LSMS) becomes very important for an in-house solution," said Matt Johnner, telecom technologies product manager - sales. "When you add number pooling, all these things are adding to the strain between the NPAC-LSMS interface. So it's crucial to have a really good-performing LSMS."