Performance of Voip Services on a Docsis Network Targeted by a Denial of Service Attack

Over 48 million end users worldwide utilize cable modems as their means of accessing the Internet at high speeds. Networks which provide access via cable modems utilize Data Over Cable Service Interface Specifications (DOCSIS) as their means of network management. As availability and utilization to the Internet increases (especially at high speeds supported by broadband access), so does the opportunity for malicious activity against those users. Denial-of-service (DoS) attacks are one form of malicious activity and one of the most common. In commonplace switched Ethernet, wired networks, a DoS attack requires relatively high levels of computing and network resources to successfully deny service. In DOCSIS-based networks, high levels of computing and network resources aren't mandatory in order to sufficiently degrade a network segment, especially when the objective of the attack is to reduce the quality of Voice over Internet Protocol (VoIP) sessions. This phenomenon hinges on the Media Access Control layer protocol employed by DOCSIS used for managing access to the upstream transmission medium. The implications of this phenomenon are widespread as end users looking for cost-saving voice telecommunications services migrate to best effort VoIP such as provided by Vonage.