In this year’s March column, I mentioned how spam on Internet telephony (SPIT) could become a big problem as voice over Internet protocol (VoIP) proliferates as a replacement for circuit-switched telephony. This month, I’m pleased to report on how our industry has gained a leg up on the competition by beating SPIT before it becomes a nuisance. As we fight for telephony market share, we can use this as another example of the depth of our PacketCable standard. What SPIT is SPIT is an application of broadcast VoIP calling. VoIP makes a broadcast call possible because each VoIP phone number is associated with an IP address. Just as email can be sent simultaneously to multiple recipients, VoIP calls can be made simultaneously to multiple IP addresses. Qovia, a firm that has a vested interest in this application and that we will discuss later, has already proven the feasibility of broadcast VoIP in a lab environment. Due to the infancy of service provider VoIP and lack of any sizable subscriber base, broadcast IP calling has not yet appeared in the real world, but appears to have a lot of potential. Telemarketers and politicians could easily use this application to implement a low cost mass announcement media. Replying to the message would be done similarly to the way a consumer replies to any other mass message: call an 800 number, go to a Web site or (gasp!) send a check via US mail. As a bonus, recent decisions on the status of VoIP as an information service imply that the current "do not call" legislation does not apply to VoIP. How SPIT might be used We can gauge the attractiveness to telemarketers by looking at the business case for telemarketing in general. Transport is the largest component of automated telemarketing costs, and as it decreases, telemarketing becomes proportionately more feasible for lower cost products. Although a typical VoIP phone-to-phone call rate is now around $0.10 per minute, trends indicate the rate will continue to drop, perhaps as low as $0.02 per minute. Dr. Fred Cohen, principle analyst at the Burton Group who specializes in telemarketing, typically uses 1/2 percent as the success rate for telemarketing calls, implying the cost per successful call to be about 200 times $0.10, or $20. He then adds $0.50 per followup call for the fulfillment (assuming low cost international call centers), which brings the total marketing cost to under $21 per sale. If we assume marketing costs to be 20 percent of total product costs, this method of telemarketing is cost-effective today for a product that sells around $100. If VoIP per minute costs drop to $0.02 per minute, a $20 product can be justified. Also, the higher the percentage of product cost for marketing, the lower the total cost of the product that can be justified as a telemarketing candidate. Magazines, for example, might fall in the 50 percent or less range, providing justification for marketing a $10 subscription when call costs drop to $0.02 per minute. The time it takes to make a sale is perhaps more important than the success rate, however. Making 10,000 one-minute calls to generate 50 successful sales with a four-line autodialer takes a little over 40 hours. Depending upon when the calls are made, it might take a week to generate those 50 sales, which negates the potential for items that sell below $100. On the other hand, a broadcast VoIP call could reach all 10,000 numbers in one minute, leaving only followup calls to takers as the remaining task. Suddenly, the market is opened to products priced at $10 and below. How to stop it Several data network monitoring companies are investigating potential technical solutions to block SPIT automatically, but most of them are more applicable to an enterprise environment than to a service provider network. For example, Qovia is a relatively new company that owns two patents on technology to recognize and block broadcast SPIT calls, but its technology has some significant limitations. The Qovia solution involves looking at packet length and duration to recognize patterns that indicate machine-generated calls. A large drawback to this approach is that it can only screen calls in progress, which limits any blocking to calls that have already been routed to voice messaging systems. To screen live calls, filtering needs to be done at call setup, and that’s exactly the way a PacketCable call management server (CMS) operates. Eric Rosenfeld, CableLabs VP Advanced Network Systems, explains: "Setting up a call in a PacketCable system involves more than sending a message. Calling and called number information is routed to the CMS, which initiates the actual connection. The total number of parties involved in a single call is therefore under control of the CMS and is typically limited under system operator control to two or three." The details of how the CMS handles the screening are up to the individual vendor. Sonit Mahey, Cedar Point Communications systems application engineering manager, pointed out that Cedar Point’s Safari C3 has two features that eliminate a SPIT scenario. "’Privacy manager’ will only complete calls from a predetermined list of numbers. Under the most secure implementation, even callers with numbers on the list will need to input a special PIN to complete the call. With the ‘no solicitation’ feature, if the calling number is not on the list of permitted callers, an announcement is automatically sent asking the caller to put the subscriber on the ‘do not call’ list." Mahey also noted that Cedar Point’s design further protects cable telephony subscribers by hiding their IP address from the network, similar to the way a firewall operates for data. Get ready When and how a systems operator promotes SPIT-free telephony obviously will depend upon how fast the problem materializes. History indicates that the telemarketing industry is quick to adopt new cost-efficient ways to reach its audience, and it’s reassuring to know that when SPIT arrives, cable already has a weapon in its arsenal that will position it among the good guys. Justin J. Junkus is president of KnowledgeLink and telephony editor for Communications Technology. Reach him at firstname.lastname@example.org.