Prepay it Again, Sam

Strike the notion that wireless prepaid services will endow themselves with the cost and efficiency virtues of wireless intelligent network (WIN) overnight. They will not. For the wireless carrier in 15 different markets, with different network infrastructures, the migration path to WIN is hazy. While technology directions and recent conferences clearly point down the WIN path, the haze clears only enough to see the obstacles ahead. The racers are set on their blocks, but the starter's gun hasn't sounded. As standards are slowly mulled over, ubiquity waits in the wings.

Conversely, VoIP (Voice over the Internet Protocol) is enabling some prepaid calling card providers to crash the market with low prices and enviable product margins. Internet Telephony Service Providers (ITSPs) continue to slip the net of access charges, settlement costs and tax liability under the fragile immunity of data traffic.

Technology issues, however, may slow the migration from higher churning prepaid services to lucrative, customer retaining postpaid services in the VoIP world. Latency delay affects voice quality. The inability to widely transmit touchtone signaling (DTMF - dual tone multi-frequency) in and beyond an ITSP's network could impact prepaid services platforms, for such as mid-call events, as well as after call completion or call tear down.

One need not ask whether a prepaid calling card from a reseller of VoIP will work from Europe or South America as well as a Sprint or MCI prepaid card will. It is safe to say it will not, not until a myriad of localized gateways spring up, but believe that the issues are being addressed and resolved.

Right Now

This all need not imply gloomy days in the haze if the focus is on prepaid services today. The technology and vendor options are many - including emerging WIN options for wireless, and the ability to treat VoIP from IP telephony gateways (for calling cards).

As Bob McCormick, sales manager at Electric Lightwave and author of the Prepaid Calling Card Source Guide, reminds us, "Whether switchnet or VoIP, or wireless, it all comes down to living in a cost-effective, usage-based environment."

Today's prepaid service capabilities are offered by a host of vendors - all pieces in the prepaid puzzle. These vendors run the gamut from network infrastructure providers such as Ericsson, Nokia and Nortel, to programmable switch providers such as Summa Four and Excel. From prepaid service platform providers such as Corsair and Glenayre, to billing and customer management providers such as Amdocs and Portal. Not to mention IVR platform providers such as Interact, manufacturers of voice boards like Dialogic, and service bureaus, such as Atlantax, for tax rating and compliance.

Platforms Come Center Stage

"All vendors compete closely on features," says John Tallarico, director of product management at Glenayre. "Most platforms differ little in feature-functionality. Differentiation is in the ability to offer a full set of services."

Glenayre's product, openMEDIA, supports prepaid wireless, prepaid calling card and postpaid calling card. It follows the service node concept - an adjunct switch - utilizing programmable switches from Summa Four or Excel, with IVR/VRU resources as a separate component embedded with Dialogic high-density voice boards. The host computers that actually control the switch and IVR/VRU are IBM RS/6000 or Sun Microsystems. OpenMedia has open client/server architecture and runs under UNIX on Oracle databases.

"Although many DOS-based platforms are available today," says Source Guide author McCormick, "under a heavy load of database access and updates, as well as managing calls, call set-up times may be even more exaggerated than the usual 4 - 12 second delay. UNIX-based options are better suited for multitasking, are more fault-tolerant, and provide more effective call resource utilization." UNIX allows for parallel processing and multithreading for efficiency and to optimize scalability.

Amdocs' Ensemble product uses a scalable UNIX architecture and usually runs on an Oracle database. It uses a three-tiered layered architecture and is rules-based and table-driven. Data tables are accessed and correlated by a layer of user-defined rules, with an underlying infrastructure layer.

. "The rules are used to introduce more complex concepts that are difficult to describe in tables," according to Shlomo Baleli, president of the R&D division at Amdocs. "Ensemble allows our carrier customers to effect rapid change, and since prepaid and postpaid services are in a consolidated environment, the carrier can benefit from changes to both service groups, or may choose to only change one."

Adds Nehemia Lemelbaum, senior vice president at Amdocs, "The other benefits as a result of consolidation in a sole database are many: reporting, fraud support, churn management." Amdocs' rules-based management system (RBMS) and online table facilities support creation of new record formats and price plans, and defines new services and switch inputs. Amdocs works with adjunct switches and CDR-based prepaid services that are SS7-based and with vendor products such as Hewlett-Packard's acceSS7. Amdocs also works with VoIP gateways, such as VocalTec and Ericsson.

The importance of the database in managing the prepaid service must not be underscored. Glenayre's Tallarico says, "The main component is the database. It allows the setup of various rate plans, and it enables efficient access and updates to subscriber data. With rating flexibility the key to going into different markets, the database must be adaptable."

Corsair Communications covers wireless only, with a focus on D-AMPS and AMPS, but can work with all wireless technologies. "We care little about the air interface - the SCP (service control point) makes it somewhat insensitive," says John Martin, director of product management for PrePay at Corsair. "We would have to modify messaging into the switch, but feasibly we can handle GSM, CDMA, 1900/1800 MHz, satellite - it could be cups on a string."

A WIN-based solution, PrePay is licensed through Ericsson on an OEM basis. As such, it is highly reliant on having an Ericsson footprint in place. While an issue for embedded carriers, especially in the United States, it is not with new carriers, especially in emerging markets. "You will see us turning up WIN-based solutions in Latin America soon," says Bill Taliaferro, director of product marketing at Corsair. "A WIN-based solution such as PrePay is ideally suited for establishing a new footprint."

PrePay, too, uses an Oracle database, functioning as the WIN service control point. The SCP runs on Enterprise-class Sun Microsystem's hardware and monitors the SS7 network, looking for triggers. The IVR unit, for recharging account and playing messages, is offered in partnership with CTI vendor Interact.

Under this configuration the SCP is the database. It stores lists of prepaid subscribers -- where the home location register (HLR) is, the rate plan, and special features. Another database generates and keeps track of voucher (card) information. It tracks each voucher, the denomination, serial number, etc. Tied to the point of sale (POS), it creates new cards, tracks depleted cards, and moves card data to and from subscriber accounts.

PrePay is a tables environment to the carrier customer, and has desktop user interface windows (client/server) for setup of rate plans, toll tables, air charges, and the like. PrePay supports all cellular handsets -- AMPS, D-AMPS, and TAPS analog used in Asia, Italy, Spain, and other countries.

To add one more trophy to Oracle's shelf, Portal Software's Infranet IPT is built on Oracle, too. Hailing from ISP roots as opposed to telephony, Infranet IPT is constructed for fluidity, given the uncertainty of the near-term Internet telephony environment. Portal Software has modeled a concept called the gateway abstraction layer (GAL), which allows rapid development between VoIP gateway APIs (application programming interfaces) and the Infranet IPT API. IPT is an event-driven, object-oriented billing engine and runs under Solaris, HP-UX and Windows NT.

"Infranet IPT steps beyond the norm in that it can manage a calling group," says Bassam Khan, principal product manager at Portal. "If a company buys a block of $10,000, IPT can simultaneously decrement and update the account block although multiple users are active. IPT prerates a call and sends a message to the gateway that 15 minutes are available on that call. If another user of the same block makes a call, the gateway can be interdicted to reduce the available minutes on the first call." Although the gateway vendors cannot support this yet, support is anticipated soon from the likes of Cisco, VocalTec and other gateway vendors.

As with Amdocs' Ensemble, Portal's Infranet IPT is Web-enabled, in that accounts can be ordered and recharged through the Web, and the subscriber can monitor call activity, such as credit decrementing. "IPT can allow immediate activation of an account," says Portal's Khan, "or can set parameters for later activation, such as on a holiday." Additionally, IPT can trigger the gateway to have the IVR play messages in another language, such as Spanish, based on initial subscriber setup criteria.

Get a Lifecycle

The prepaid lifecycle depends on the environment: wireless (WIN and non-IN), circuit-switched (SS7 and non-SS7) or VoIP. However, functional similarities prevail across all environments.

Although Corsair's PrePay and Glenayre's openMEDIA products are functionally alike, Corsair is WIN-based and Glenayre is not, to date. However, Glenayre's platform handles prepaid wireless and calling card, as well as postpaid calling card. Amdocs handles all wireless types, as well as wireline services, such as prepaid calling card, and supports VoIP. Portal's product is today intended exclusively for VoIP product applications and other ISP and ITSP applications.

Cards or vouchers are created in a database and fulfilled physically and put on the "shelf" (physically and logically). The voucher contains an encrypted number, and when the subscriber calls the instructed number, such as *333, the infrastructure recognizes it as a call to the prepaid IVR. Portal and Amdocs allow Web-enabled ordering and activation. Amdocs allows credit transfers in an e-commerce mode, utilizing CyberCash's functionality. Portal allows real-time crediting of accounts through credit card processing houses such as FirstUSA.

Once the prepaid wireless system is activated, through varying methods, the mobile identification number (MIN) and electronic serial number (ESN), the subscriber's identity, is loaded into the appropriate home location register (HLR). Also, the system transfers funds in the database associated with the PIN or encrypted number on the voucher from the "shelf" to the subscriber's account. Now in an active state, the infrastructure is ready to allow calls.

As a wireless prepaid call is made in a WIN environment, the switch sends an Interim Standard 41 (IS-41) message to a prepaid device such as Corsair's PrePay over the SS7 network. IS-41, especially IS-41C, allows for initialization, configuration and protocol-related data to be exchanged between the network and application devices.

The switch or mobile services switching center (MSC) recognizes the call from the prepaid customer based on the MIN. The prepaid platform verifies the subscriber, acknowledges funds, looks at location and time, where the call is to, and determines components for charges on the call (so much airtime, toll time, etc.) by accessing data in tables. Rate plans are applied, talk time is computed based on funds in account and based on call scenario, and the system predetermines the amount of talk time allowed.

According to Amdocs' Baleli, in a WIN environment, Ensemble relies on an indication that a call started from the switch, based on an SS7 message. The Ensemble rating engine is accessed to calculate price plan, time and call points, and call monitoring occurs until call disconnect, with a final customer balance update in post-rating, which considers things such as split-period charging (on-peak to off-peak).

Corsair's PrePay sends a message to the switch after pre-rating, and the switch sets a timer. In VoIP, a platform such as Portal's Infranet IPT sends a message to the gateway, and the gateway has the fundamental timer. Pre-rating in both worlds has predicted how much time a given call is allowed, and as a call progresses, post-rating gets a message from the switch or gateway, which indicates actual talk time. A CDR or event record is created, and PrePay or Infranet IPT computes what decrement should be applied to the account and updates the database. The subscriber's account is adjusted quickly - a query by a customer care agent would see information immediately (in real time). This is an advantage over other types of wireless prepaid architectures, at least CDR-based, in that CDR-based has a one-call exposure.

Since most prepaid systems have configurable thresholds, if the subscriber keeps talking after hearing switch-generated whisper tones the switch will tear down the call. A message is sent back over the SS7 network that the call is terminated and the account is set to zero. Most systems, such as Glenayre's and Corsair's, can reroute call data back to the platform IVR so a message can be sent to subscriber to recharge the account. At the zero balance phase, no calls are allowed in or out as the system awaits recharge. E911 calls and calls to customer service are set up in the switches for dial-around the prepaid platform. Expiration dates will also set accounts to zero, resulting in breakage, and are a carrier-defined threshold.

If an account stays in zero balance too long, the system automatically de-provisions them, and removes data from the HLR for wireless, and the subscriber can no longer make calls because the account (MIN and ESN) is no longer recognized. Likewise, funds existing past expiration are zeroed out. MINs go through a cooling period before they are recycled and placed back in the pool for reassignment.

Prepaid platforms allow for recharging through IVRs using voucher transfers, or through credit cards. The subscriber can speak to a customer care agent, or in the case of Amdocs and Portal the subscriber may transact over the Internet. Carriers and their vendors are now looking at financial institutions' ATM machines as recharge mechanisms.

Interface Points

Plug into published and standardized APIs, right? Don't count on it yet. Although most vendors are paying attention to emerging standards from forums such as OBF, interfaces require varying degrees of customization. Carriers must consider the experience of vendors such as Glenayre and Amdocs, but must also consider the innovation of vendors such as Portal, with its gateway abstraction layer, and Corsair's WIN-based functionality.

According to Amdocs' Baleli and Lemelbaum, Amdocs finds the IP world a much more open environment with which to interface than the SS7 circuit-switched environment. In the non-IP environments, SS7 and IN vendors have vertically integrated prepaid solutions with their systems. "This makes it harder for the billing vendor to integrate," says Baleli. "Both from a technological and a business point of view the open IP environment created by the gateway/gatekeeper vendors makes it easier for Amdocs to supply a real-time, robust, network-oriented prepaid solution," Baleli continued.

The switch or gateway to the billing system or prepaid platform interface is key. Although WIN infrastructure providers are working with IS-41 for interface messaging, vendor switch to vendor switch messaging and routing are not standard. Likewise, the VoIP gateway providers such as Cisco and VocalTec do not offer the same gateway interface parameters - thus Portal's gateway abstraction layer.

Prepaid systems interface to traditional POS applications, as well as Web-based POS for Amdocs and Portal. Glenayre's openMEDIA interfaces directly to activation software. An API was developed in order to interface with Alltel's Virtuoso product, which allows activation of the number (MIN) in the mobile switch, while simultaneously activating the number in the openMEDIA application. openMEDIA communicates using a standard message set and APIs so that different billing applications and POS applications can interface. The message set contains MIN, ESN, rate plan, and other subscriber related data.

Glenayre's Tallarico says, "A key interface point is provisioning to network operations using SNMP for alarming and monitoring type capabilities. SNMP allows different monitoring systems to receive messages and log files." Glenayre uses EcoTOOLS from vendor Compuware. EcoTOOLS provides centralized control of business-critical applications through simultaneous monitoring and correlation of data, and incorporates threshold and alarm capabilities. This helps to give operations departments a dashboard of continuous performance monitoring across the entire platform. "For carriers with deployments ranging across many markets this is very important," adds Tallarico.

Amdocs interfaces the Ensemble Web front end (for PIN set up and activation) to a CyberCash e-commerce application for secure credit card transactions. It also allows use of the Internet for recharging, and for customer adjustments. Since Amdocs is a full billing and customer management solution, it can collect call history for fraud and churn management. Within the Ensemble suite are OLAP and data mining applications for business analytics. These tools are not typically found in stand-alone prepaid platforms, although Corsair's PrePay has a reporting capability for all data in the database-messages, taxes, traffic - and allows carrier-defined CDR retention.

Of Signaling and Such

"Many prepaid platforms installed today are not SS7-compatible, but later versions tend to be," says author McCormick. "No SS7 means a delay of 4 to 12 seconds on their calling platform for call set up."

"Software and hardware in prepaid platforms must be SS7 compatible," says McCormick, "otherwise the benefit of SS7 call set-up speed is lost." The SS7 database signals the switch and sets up the call before to the call signal comes in by separating the voice side from the data side of the call. Information such as routing data related to 800/888 numbers (such as dialing a prepaid IVR), calling party number and present location data for roaming wireless users are all carried over SS7 signaling.

The SS7 messages manipulated by Amdocs' Ensemble come from the ISUP/TCAP message groups. ISUP, integrated services network user part, is SS7's call control part, and allows for call status checking. Messages manipulated include initial address message (IAM), seize, answer, release, and other triggers or operators. TCAP, transactional capabilities application part, is needed by transaction-based services, such as prepaid calling card, to exchange information between a pair of signaling nodes. Corsair's Sun Microsystems SCP monitors the SS7 network and looks for triggers, and sends IS-41 supported messages. IS-41 supports a string of encoded and decoded message commands, including administrative functions for identifying the source of incoming messages and message types, i.e., prepaid.

"Communication between the Corsair SCP and the prepaid IVR is through TCP/IP so that account balances can be tracked/updated," says Corsair's Martin. As described previously, a message is sent back over the SS7 network when the call is terminated and the account is set to zero. The system can reroute a call back to the IVR so a message can be played to the subscriber to recharge the account.

"Given the status of WIN standards," says Glenayre's Tallarico, "we are working independently with switch manufacturers who have developed proprietary message sets. In some cases IS-41 is supported, but proprietary protocols prevail."

Up and Coming Understudy VoIP

From a prepaid services application standpoint VoIP is not that different from circuit-switched. As indicated in the lifecycle, the functionality is similar. According to Amdocs' Lemelbaum, "The VoIP difference is that the IP gateway handles the calls, yet communicates well with the Ensemble billing system. The gateway lets us know when a call starts, Ensemble lets the gateway know account details, then the gateway indicates when a call ends. It's a split responsibility - the gateway handles call monitoring and Ensemble handles billing and accounting, as well as customer management. The gateway has no memory - no database - the memory is in the billing system."

Portal's Khan explains, "The intelligence for timing the call is in Infranet IPT, and is controlled by sending events. Once the gateway indicates call start, IPT authorizes the call and pre-rates it to let the gateway know how long the call can be. IPT can generate an event saying 'extend the call or cut off call,' although the gateways are not yet equipped with intelligent listeners to support this."

Just as in a circuit-switched network, a gateway is expected to accept a "long #" (tone) to allow for additional calls. With Infranet IPT it is a stop event to the system. For this and other touchtone signaling, IPT is abstracted out from DMTF by the gateway. The gateway intercepts the DTMF code, but the application determines what the caller is really trying to do.

While new protocols allow for conveyance of DTMF signals out of band (separate from voice traffic), it is not standardized. Prepaid calling cards need DTMF capability. While phone-to-phone connections within a given network can do proprietary out-of-band DTMF signaling - which many gateway vendors are provide - off-net calls are more questionable.

Tax, Tax, Tax

"Since Ensemble is consolidated on a single database," explains Amdocs' Baleli, "functionality used on one product or service can be used for the others -- such as taxation. The same modules or components are used on prepaid services as on postpaid."

In the Corsair offering, the carrier can set values in the system by percentage, broken out to separate general ledger codes. But there is no physical jurisdiction capability. Glenayre skirts this problem by sending files to service bureau Atlantax on a post-batch basis. The carrier can set up a blended tax rate applied to the overall per-minute rate. Atlantax applies the actual tax rating and manages the tax compliance. Taxation for prepaid calling cards is Atlantax's largest tax rating business, followed by wireless.

Worth Bishop, executive vice president and CFO at Atlantax, describes the tax compliance life cycle; "Our prepaid calling card clients send us files of their CDRs at least monthly, more often if volume demands. We feed the data to our tax rating system, which calculates the applicable tax, depending on jurisdiction, for each CDR. The system addresses over 5,000 tax jurisdictions today."

Dial-around compensation for pay phones is increasingly an issue tied to prepaid calling cards, Atlantax is now a clearinghouse for managing the prepaid aspects and the payment due to the pay phone vendor. The prepaid card company sends a CDR file, Atlantax matches it against a database of pay phone ANIs, and calculates how much is owed to pay phone vendors, the obligation due from each prepaid card company, and the payment due to payphone provider. Bishop explains, "The function amounts to accounts payable for the prepaid card companies, and accounts receivable for the pay phone service providers - along with collections and funds transfer."

Along the Way

The migration path to WIN in the wireless world is not so much an issue with the back-end SCP and back-office applications, because the functions remain similar whether WIN-based or in a service node scenario. The call processing pieces are the most likely candidates for change, in that the entire network infrastructure will be expected to manage WIN, and right now those solutions are chiefly proprietary. Meaning a lot of issues need to be resolved in a multivendor network environment, or to interconnect between carriers' networks. Conceivably, while a larger carrier is migrating to WIN, it can operate in a hybrid environment, such as part WIN and part service node.

In service node a call is intercepted by a switch translation on the MSC, whereas in a WIN-based solution it is more dependent on the HLR to now determine a prepaid account, and interrogation is more against the HLR rather than the switch itself. In WIN the HLR has a direct connection to the overall platform, determining call treatment for prepaid versus postpaid.

Surprisingly, this all means little to the billing nucleus, even while everything around billing is in flux.

Similar issues apply to VoIP as they do in the wireless world. But while it makes economic sense to do so, the IP network model will advance and today's issues will be resolved. Yet don't expect large embedded carriers to hurry to routers and gateways instead of switches and SCPs except where it makes the most sense, such as in economies found in some transport. With Cisco's acquisition of Summa Four, it is hurrying to offer its AP-VS3 VoIP platform along with its VCO/4K programmable switch, giving carriers the option to perform routing between the IP network and the PSTN. The VoIP and WIN starting gun has sounded, but it promises to be a long, grueling race.

Frank Slavick is a telecommunications consultant based in Denver, Colorado, specializing in product development, new business development, and billing and customer management. He can be reached at 303/554-0958, or at fslavick@earthlink.net.