Voice over IP (VoIP) promises the benefits of lower cost and the creation of new applications that integrate telephony into business systems. Manufacturers and service providers are racing to develop and deploy VoIP products and services, while standards bodies are refining international recommendations – such as H.323 and SIP – to increase the security, interoperability and performance of VoIP services. Unfortunately, hackers are already writing DoS attacks that exploit weaknesses in VoIP systems, and both service providers and enterprises are finding that firewalls can degrade VoIP performance.
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