ABSTRACT Two standards currently compete for the dominance of IP telephony signaling: the H.323 protocol suite by ITU-T, and the Session Initiation Protocol (SIP) by IETF. Both of these signaling protocols provide mechanisms for call establishment and teardown, call control and supplementary services, and capability exchange. We investigate and compare these two protocols in terms of Functional...

Network intrusion detection systems (NIDSs) face the serious challenge of attacks such as insertion and evasion attacks that are caused by ambiguous network traffic. Such ambiguity comes as a result of the nature of network traffic which includes protocol implementation variations and errors alongside legitimate network traffic. Moreover, attackers can intentionally introduce further ambiguitie...

Since the inception of telephony, the public switch telephone network (PSTN) has had major impact in everyday life. The widespread adoption of VoIP has totally revolutionized the telephony industry. With many free services for the users, VoIP is favored over the traditional PSTN. A major concern for VoIP is voice quality, as it is a network-based packet switching technology. VoIP will come in h...

Circuit switching, suited to providing real-time services due to the low and fixed switching delay, is not cost effective for building integrated services networks bursty data traffic because it is based on static allocation of resources which is not efficient with bursty data traffic. Moreover, since current circuit switching technologies handle flows at rates which are integer multiples of 64...

Within the traditional telephone system a certain level of quality and security has been established over the years. If we try to use IP Telephony systems as a core part of our future communication infrastructure (e.g. as classical PBX enhancement or replacement) continuous high availability, stable and error-free operation and the protection of the privacy of the spoken word are challenges, th...

Over the past decades, construction firms have been using several off-the-shelf telecommunication tools and techniques to provide the communication means necessary to their mobile personnel on the jobsite. It is obvious that two-way radio transceivers such as walkie-talkie were the de facto standard adopted within the industry at first sight and for many years for very good reasons i.e. inexpen...

This document defines a new attribute for the Telephony Routing over IP (TRIP) protocol. The attribute associates protocols/services in the PSTN offering authorized prioritization during call setup that are reachable through a TRIP gateway. Current examples of preferential service in the Public Switched Telephone Network (PSTN) are Government Emergency Telecommunications Service (GETS) in the U...

The explosive growth in Internet traffic has created the need to transport IP on high-speed links. In the days of low traffic volume between IP routers, bandwidth partitions over a common interface made it attractive to carry IP over a frame relay and/or an ATM backbone. As the traffic grows, it is becoming more desirable to carry IP traffic directly over the synchronous optical network (SONET)...

ACME, an automated tool for generating and evaluating the quality of VoIP calls, is presented. ACME examines the availability of bandwidth and processing capacity to determine the largest number of simultaneous calls that a node can operate in a given topology, besides supporting pre-programmed schedule of VoIP experiments. Demos of ACME usage as a capacity estimation tool and as an instrument ...