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”Hardware Embedded Firewall for a VoIP Telephone”

Alexander Papantonatos


Many Modern Internet applications are targeted towards mobile and portable platforms. Security is a major issue in present as well as next generation mobile Internet applications. Well established security measures, such as the firewall or packet filter, can be found exclusively in large central stationary Internet nodes. With the advent of high-speed wireless data networks and wide-spread use of fixed wired networks more and more mobile and embedded information systems offer Internet connectivity. INTRACOM’S VoIP phone desk is a desktop telephone device offering telephony services over IP networks. As a first line of defence against external security threats an embedded firewall is to be integrated with the VoIP phone. A few hardware implementations of a firewall have been designed in the past, although none qualifies as an embedded firewall with small area and low memory requirements. The purpose of this project is to identify suitable algorithms that will allow the design of a deeply embedded firewall that will meet the stringent timing requirements of a system operating on a 10/100 Mbit/s Ethernet network. In order to evaluate the proposed algorithms various implementations are compared. One of the results of this investigation is a novel algorithm for point location in a finite set of integer ranges. Finally, a model design of an embedded firewall using the proposed algorithms with memory requirements as low as 64Kbytes is presented and discussed.