VoIP: A comprehensive survey on a promising technology
Computer Networks: The International Journal of Computer and Telecommunications Networking
A framework for seamless service interworking in ad-hoc networks
Computer Communications
A sender-oriented back-track enabled resource reservation scheme
ICCNMC'05 Proceedings of the Third international conference on Networking and Mobile Computing
Application-independent session mobility between user terminals
MATA'05 Proceedings of the Second international conference on Mobility Aware Technologies and Applications
Review: VoIP: State of art for global connectivity-A critical review
Journal of Network and Computer Applications
| Hi-index | 0.00 |
One of the major challenges for next-generation IP networks is to provide new, attractive multimedia services. This includes traditional telephony (voice over IP) and the interworking with legacy telephony systems. In addition to the general problems regarding the support of realtime services in the IP network, e.g., quality of service, voice over IP focuses on the control of advanced features such as supplementary services well known from telephony and on the mechanisms for their fast and efficient development and deployment. The two most promising approaches in the area of multimedia over IP are the protocol suites H.323 (ITU-T) and SIP (IETF). Several comparisons of these two protocols have already been published, but comparisons of their service architectures have been rarely addressed. This tutorial describes and compares the service architectures of H.323 and SIP. The basic protocol architectures are explained, followed by an in depth evaluation of the service implementation mechanisms. The analyses focus mainly on the control of telephony supplementary services in H.323 and SIP and are backed up by detailed examples. Although the two protocol architectures are quite similar, it is shown that there are considerable differences regarding their supplementary service architectures. H.323 (together with H.450) has been especially focused on supplementary services, smooth interworking with the PSTN, and interoperability between different implementations. In this respect, it has clear advantages for IP telephony applications. SIP has been designed with a broader scope, providing more generic syntax and semantics regarding feature definition and session description. Since the SIP standards do not describe details of possible application and service features, this bears the danger of interoperability problems, e.g, for supplementary services. SIP offers advantages for non voice over IP services and applications. A coexistence of both protocols can be foreseen, stressi- ng the importance of interworking between them.