Customized interrupt level packet manipulation for VOIP gateway applications
Original Publication Date: 2008-Mar-26
Included in the Prior Art Database: 2008-Mar-26
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Separate networks (e.g. VoIP: Voice over Internet Protocol) are connected over gateways, so that after call establishment a continuous flow of RTP/RTCP packets between these networks is setup (RTP: Real-Time Transport Protocol, RTCP: Real-Time Control Protocol). Concerning the performance, an efficient manipulation of significant amount of packets in e.g. IP networks is necessary especially when the usage of specialized network processor based solutions is restricted by price per unit. In contemporary solutions packet handling is often performed with process space of the operating system. A generic approach is represented e.g. by the netfilter component of a Linux operating system, which includes so called IP tables and hooks within the so called Linux kernel in order to intercept and manipulate network packets. The netfilter framework allows the system administrator to define rules for the handling with network packets. Nevertheless, there is more functionality required than normally provided by IP tables.