By Khali Henderson

VoIP peering, a system for direct exchange of VoIP traffic, is gaining momentum as separate efforts to unite the growing number of VoIP islands are attracting not only ITSPs and long-distance carriers, but CLECs, MSOs and even enterprises.

Cable company RCN Corp., for example, announced in late March it would connect to the Voice Peering Fabric (VPF) started by Stealth Communications Inc. in fall 2003. Stealth CEO Shrihari Pandit says the deal is significant for the VPF not only in that RCN is the first MSO to join, but in RCN’s commitment to support the VPF by connecting to the N.Y. PoP and hosting new VPF PoPs in Boston and Chicago markets. VPF also is available at telx Atlanta, a carrier hotel at 56 Marietta St. owned by telx Inc. The VPF minutes market processed 2.5 billion minutes in 2004, and with the RCN and other pending agreements, Pandit says the VPF could reach 6 billion minutes in 2005.

Among its more than 70 members, the VPF already has some noteworthy voice over broadband carriers. 8×8 Inc. (Packet 8), China Telecom, Net2Phone Inc. and Popular Telephony Inc., to name a few. “We are starting to get a lot of traction with the CLECs,” Pandit adds. One reason, he says, is that they are deploying VoIP networks in their core and don’t want to bear the costs of translating calls back to TDM to hand-off.

“If they can move that call through the VPF ENUM registry, they can save the expense of converting a call back to TDM. They save on the trunk capacity and termination charges and other types of database lookup fees normally associated with terminating a call on the PSTN. A lot of those cost elements are removed by using our system,” he says.

The VPF ENUM registry is an optional free service offered to VPF members - carrier and enterprise. By uploading their telephony numbers into the registry, they can deliver calls to other numbers in the registry based on their IP address, thus avoiding touching the PSTN.

“Last year, we processed 46 million calls - free calls - that bypassed the PSTN totally” using the VPF ENUM Registry, says Pandit. “All that traffic was IP end-to-end through the Voice Peering Fabric. So, 46 million calls equals 300 million minutes roughly, which is pretty significant. We have folks like Net2Phone, Packet 8, a couple of CLECs. … RCN is now part of the ENUM system as well.”

With RCN on board, the VPF ENUM Registry will grow beyond its current inventory of 5 million numbers, raising the probability of an on-net “peering” call. RCN will be marketing participation in the VPF and the ENUM Registry to its enterprise customers.

“What makes our ENUM registry very attractive is that the Voice Peering Fabric is the first and only Layer 2 Ethernet backbone dedicated for voice-over-IP traffic,” explains Pandit. “When you couple the VPF backbone with the ENUM registry it means that people can route phone calls in a secure, closed environment. People want voice over IP, but they want the quality and reliability of the PSTN. The VPF really helps talk to those concerns of enterprise customers and even some of the large carriers.”

Pandit says enterprises began connecting into the VPF on their own accord last summer. Typically, they connect over Ethernet into the closed Layer 2 platform. In so doing, they are able to choose their originating and terminating carriers for price, quality and redundancy.

“A lot of them are doing their own LCR,” he says, noting it’s on a limited basis but is representative of a “radical shift” compared to how they used to do business, which was connecting via PRI circuits to their local and long-distance companies. “With the VPF, the paradigm is changing; they get one connection into the VPF and they can pick and choose from the market who they can use for inbound and outbound. They can choose multiple carriers for each of those functions,” he says.

Interconnection and private or carrier ENUM registries are key components of VoIP peering services, which offer cost and functionality that promise to make VoIP an even greater threat to the PSTN.

“The idea is to avoid the legacy PSTN and, therefore, avoid fundamental charging of per-minute per-call, and to gain the benefitsof end-to-end IP services,” says Eli Katz, founder and CEO, XConnect Global Networks Ltd., a Europe-based VoIP peering provider that in late March launched in North America by signing iBasis Inc. and Yak Communications Inc. Earlier members were Gossiptel, a consumer VoIP service based in the United Kingdom; Telio, a VoIP service provider based in Norway; and Spanish consumer provider VozTelecom Sistemas S.L.

There are several reasons to have a private ENUM, Katz says. Service providers may not want to reveal publicly their daily subscribers numbers, which could be determined from a public database. A private database provides lookups without revealing how many came from each member. Also ENUM databases are very large and require advanced management technology. Providers, such as XConnect, may claim to have superior lookup systems to speed connections.

Another service is interoperability. A VoIP peering provider can choose to provide protocol mediation between any number of systems, including SS7, H.323 and SIP. Also some service providers use different codecs, which may require mediation. A VoIP peering provider could guarantee interoperability with just one connection.

“We provide normalization so you as a VoIP carrier provide one interconnection to us, and we provide a service to deal with all the messy stuff, like a large hosted session border controller,” says Katz.

With its North American launch, XConnect announced it also is partnering with NexTone Communications to provide the first certified “XConnect-Ready” VoIP session border controller. In addition to ENUM registry and interoperabity, security is perhaps the most critical component of the VoIP peering service, says Katz. As bad as it is when one service provider has a security breakdown, the issue can be compounded if the security threat is passed out of the network.

XConnect, Katz says, will provide several initial services in this area. First, what the company calls “protocol cleansing and validation” to ensure that differences in implementations of protocols will not injure another member’s network. If one service provider does a slightly different implementation of the time and date in SIP, for example, “your SIP proxy will ignore it, if you are lucky,” says Katz. “If you are unlucky, it will hiccup, and if you are really unlucky, it will blue screen.”

XConnect also plans to offer a validated caller ID to prevent faking the origination number of a call. This issue is getting a lot of attention right now, with work going on in the Internet Engineering Task Force (IETF) with SIPCert to develop systems to validate the origin of a SIP call.

A third area of concern is “spit,” unsolicited SIP phone calls. “The impact of spit can be worse than classic spam,” says Katz. “If you come down in the morning and, of 100 voice mail messages, 97 are spit, that is serious.” XConnect will offer techniques to identify and block spit. “This is very much an evolving technology,” admits Katz, “but we have in place basic spit protection.” He says the company also is looking at implementing elements of Security Assertion Markup Language (SAML), a new technology in this area.

Last, XConnect will offer two settlement options: a standard minutes exchange and settlement-free exchange, where service providers exchange traffic without settlements on the assumption that traffic essentially will be symmetrical. “And when this happens, this is really the beginning of the end of the PSTN,” says Katz.