Paper: Mathematical Approximation of Delay in Voice over IP


This paper introduces a novel method of approximate calculation of delay in voice over IP systems. The proposed method relies on mathematical operations like interpolation and integration to produce a continuous function. This continuous function shows the delay in different times. The paper shows a detailed example of applying this method successfully to a sample call. The resulting delay function can help in better understanding of the variations of delay in different times and how it is affected by network load.


Citation Information:

Mohammed M. Alani, Mathematical Approximation of Delay in Voice over IP, International Journal of Computer and Information Technology (IJCIT), ISSN: 2279-0764, Vol. 3, Issue 1, pp. 78-82, January 2014.

Implementation of AES in Voice over Internet Protocol

The paper is aimed to provide an implementation and evaluation of Advanced Encryption Standard (AES) to a Voice over Internet Protocol (VoIP) system. The research in this paper also concentrates on evaluation of Quality of Service (QoS) parameters and the effect of implementing the AES to voice packets. Although, the security provided by encryption is of unique importance to voice signals, designs must take into concentration keeping the QoS parameters in acceptable values. The VoIP model used in this paper was H.323 model. And encryption was implemented between the End Point (EP) and GateKeeper (GK) and between GKs too. The two scenarios evaluated here were calls made between EPs lying on the same GK and on different GKs.
Three QoS parameters were evaluated in this paper; delay, jitter, and loss. These parameters are the most influential on the quality of the voice session.
The implementation carried out in this paper by using Asterisk software as the GK and JCPPhone as the EP. A software module was added to Asterisk and JCPPhone to implement AES.
This study has shown that the implementation of AES in the used call models has given good QoS parameters for long and short distance calls. This implies that the integration of AES in VoIP future applications is possible.

Keywords: AES, encryption, computer network, VoIP, IP-Telephony, H.323, and VoIP security.

Citation Information:

Siddeeq Y. Ameen, Fawzi Alnaima, Mohammed M. Alani, Implementation of AES in Voice over Internet Protocol, accepted for publishing in Gulf University Journal (ISSN:1985-9562).

Paper: Development of a VoIP Security System Based on H.323 Protocol

In this thesis a secure IP-Telephony framework is proposed. This framework relies on H.323 and covers two of the most important weaknesses that were in the original H.323 and were not covered in an efficient and easily implementable way. These two weaknesses are secrecy of voice data traveling from one EndPoint to another, and authentication between GateKeepers when calls made are Inter-GateKeeper calls. In the suggested framework, Advanced Encryption Standard and HMAC-SHA1-96 were used to overcome the weak points of the original H.323.
The suggested framework was implemented and tested and has proved strength over most popular IP-Telephony attacks and provided acceptable quality of service as compared to other solutions of the H.323 security loopholes. The implementation was tested for two different scenarios; calls placed on EndPoints laying in the same local area network, and calls made over the Internet with EndPoints laying in different zones.
For the local area network calls, the delay was 61 milliseconds, and the jitter was 8 millisecond, with an average loss of 0.93%. For the Internet-separated EndPoints, the delay was 265 milliseconds, and the jitter was 41 milliseconds, with an average loss of 1.22%. These values were calculated for 1000 calls.
The implementation environment included Asterisk software as the GateKeeper software, and JCPPhone as the EndPoints software. The Asterisk version used was AsteriskNOW beta5-x86. It was installed on Linux servers.
The proposed system has shown more resistance towards the most common three IP-Telephony attacks; toll fraud, eavesdropping, and denial of service. The features of the proposed system were compared with the original H.323 set, Session Initiation Protocol, and H.235 Annex D.

Citation Information:

Mohammed M. Alani,  “Development of a VoIP Security System Based on H.323 Protocol”, PhD Thesis, Computer Engineering Department, College of Engineering, Nahrain University, May, 2007.


Mohammed M. Alani,  “Development of a VoIP Security System Based on H.323 Protocol”, PhD Thesis, Computer Engineering Department, College of Engineering, Nahrain University, Baghdad, Iraq. May, 2007.