Abstract
VoIP is the use of Internet protocols to provide telephone services that have previously been delivered over traditional telephone networks. Advantages of VoIP include cost, portability, and functionality which are the main reasons that many consumers and small businesses are considering this technology as a replacement to traditional telephone services. There are however risks associated with VoIP services which impact quality and security of the phone system for voice communications. This chapter reviews issues related to quality and security as faced by consumers and small businesses. Recommendations are provided to improve call quality and mitigate threats faced in the VoIP environment.
TopBackground
The concept of utilizing the Internet to transmit voice conversations is not a new one. The idea dates back to the 1970s, though the data rates and connectivity available to most individuals made it impractical for common usage at the time (Schulzrinne, 1999). As Internet access proliferated in the mid 1990s, companies such as Vocaltec emerged selling software to facilitate VoIP conversations (Varshney, Snow, McGivern, & Howard, 2002). The products generally required both parties in a conversation to be running the same proprietary software on their computers, and did not provide a path to the PSTN, severely limiting their usefulness for general voice communications.
Since that time, VoIP technologies have continued to evolve, including establishment of several important standards. Development of the Session Initiation Protocol (SIP) has helped to standardize procedures for establishing, changing, and terminating of Internet-based phone calls (Schulzrinne & Rosenberg, 1998). Development of codecs for encoding of the audio signal based on available bandwidth and capabilities of the hardware and software at each end point (Garbin & Gharakhanian, 2006) has facilitated communications between software and hardware of multiple vendors, as well as connections into the PSTN (Varshney et al., 2002). As high speed Internet access has continued to become more ubiquitous, an increasing number of businesses and consumers have realized the significant cost savings that can be realized by switching some or all of their voice services to VoIP.
Key Terms in this Chapter
PSTN: Public Switched Telephone Network. The traditional circuit-switch telephone network operated by local and long distance telephone companies.
SIP: Session Initiation Protocol. One of several protocols that enables VoIP communications by assisting with determining the location of the destination user, and negotiating the encoding scheme and calling features to be utilized during the VoIP conversation (viop-info.org, 2007).
Skype: VoIP service provider owned by e-Bay that uses proprietary protocols for VoIP communications with other Skype members and to the PSTN. In general, Skype phones and adapters are not compatible with SIP-based services (Waclawsky, 2007).
VOIP: Voice over Internet Protocol. Using Internet protocols for voice communications over local and wide area networks including the public Internet.