Internet from the wall plug and telephone on the Internet – these topics have been discussed repeatedly in the past few years. What’s now serious about VoIP?
Nölle: The data networks in use so far were unsuitable for real-time services like telephony. A transmission delay of a couple tenths of thousands of seconds has not been critical so far. But telephony on the Internet must pay particular attention to transmissions without any delays so that the participants in a conversation do not trip over each other’s words. Additional network effects can lead to the loss of data packets on the network and a lessening of speech quality. For the first time, the new network technology now enables preferred transmission of speech so that other, less time-critical services can be slowed down during network overloads.At the same time, the offerings are becoming more and more similar. Telephony on the cable TV line or DSL is already common. The buzz word is triple play. It means that speech telephony, data applications, and TV offerings (IP-TV) all run on a single data connection. In the near future, TV transmissions will enter a living room alongside VoIP.
And why do small and midsize companies delay implementation of the new technology?
Nölle: These companies have looked skeptically at new technology so far. VoIP was considered immature and was linked with poor speech quality. In the early phases, VoIP migrations were often not planned cleanly, so many customers were, in fact, dissatisfied with the solution.
What security and quality problems still need to be resolved with VoIP?
Nölle: Comprehensive encryption of a conversation has not appeared so far. But that also applies to public telephone services. However, companies can completely encrypt VoIP traffic among several locations. All the network branches used for speech transmission must guarantee sufficient bandwidth and brief delay times on the network.
How can VoIP users protect themselves from having their conversations hacked and misused?
Nölle: Correctly installed hardware and the required security package at least make it difficult for hackers. Even a personal password protects from unauthorized access to VoIP hardware. For example, the Secure Real Time Protocol (SRTP) standard prevents third parties from participating in a VoIP conversation by encrypting the conversation’s data. Signaling information that contains the telephone numbers of both parties can also be encrypted.
How have international standards for VoIP fared? Who’s pushing them ahead?
Nölle: Various authorities are working on standards. The International Telecommunication Union (ITU) is developing international telecommunications standards. The Internet Engineering Task Force (IETF) follows an Internet-oriented approach mirrored in the popular Session Initiation Protocol (SIP) standard. The 3rd Generation Partnership Project (3GPP) and the European Telecommunications Standards Institute (ETSI) are currently working on the convergence of fixed and mobile networks.
Who is the audience of the VoIP-Info.de portal?
Nölle: One group consists of business customers who want information on the technology of VoIP, are looking for a supplier, or who want to work on projects. Another group consists of private customers. The portal offers them information on the technical basics and an option to query rates. All visitors find up-to-date news, literature, and notices of events.
Are there similar portals in other countries?
Nölle: Yes. The consumer portal at http://voxilla.com/ by Voxilla, the English-language news portal at http://www.voip-news.com/ by Tippit Inc., or the technical http://www.sipcenter.com/ by Ubiquity Software Corporation.
Your home page features an SIP address for telephony. The address looks a lot like an e-mail address. How does that work?
Nölle: A telephone number in e-mail format is now more of a game for users of soft clients or VoIP hardware end devices. It works like a normal telephone number except that instead of just a number, this target address is given.
What roles does ENUM – a solution that can be used to reach private and business telephone, fax, Web sites, and e-mail with a single telephone number – play for the further spread of VoIP?
Nölle: ENUM offers an entire palette of technical perspectives. First of all, it enables calls to be directed from a fixed network to a VoIP network, and vice versa. And second, several additional functions of the home zone can be implemented with ENUM so that users get better conditions for home telephony. And third, a caller can use ENUM on an end device to see if a particular number on a fixed network can be reached with VoIP.
What do you say to the accusations that cheap prices for VoIP are partly just a bluff?
Nölle: As is true of all telephone rates, customers should compare rates carefully and consider the conditions – like charges per second or, more unfavorably, charges per minute. Call-by-call suppliers themselves usually use VoIP networks, so it’s understandable that the prices would be similar to those of VoIP providers.
Who would truly find VoIP better and more economical?
Nölle: Frequent callers today have the best terms: a flat rate of just about 10 Euro for calls on the fixed network. The rate is available from VoIP and fixed network suppliers. In particular, calls on mobile networks and abroad are usually more economical on VoIP. But customers must check individual cases and compare the rates of various suppliers.