A Survey of Bandwidth Optimization Techniques and Patterns in VoIP Services and Applications

As Internet Telephony unveils a communication system that allows for the conduction and reception of voice signals and data over the internet network, the volume of voice traffic and (or) packets on IP networks have grown substantially. However, a crucial problem imminent is that of inefficient bandwidth utilization which is mostly as a result of header overheads resulting from the attachment of a big header size (40 bytes) to small payload size (10 to 30 bytes). Now the broadband telephone industries reveal a lot of business prospects in revenue, with great benefits and rewards for current and could be investors. However, these service providers must continue to make out ways of keeping themselves relevant and strong amidst great competition. The quest is to condense the amount of bandwidth being wasted, or better still; improve the utilization of bandwidth which eventually enhances network performance and VoIP quality of service. Numerous schemes and techniques have been suggested to meet this need. This article surveys the various techniques adopted for optimising bandwidth for VoIP services over the period 1999-2014. The improvement of bandwidth can be realized through; silence suppression measure of repressing the silent portions (packets) in a voice conversation using Voice Activity Detection algorithm; by so doing, the transmission rate during the inactive periods of speech is reduced, and thus, the mean transmission rate can be reduced. A second measure is packet header reduction which defines a process of multiplexing and de-multiplexing packet headers to curb excesses. Voice/ Packet Header compression is considered the most productive of all the techniques, offering a scheme where VoIP packets are compressed from the 40 bytes of size to a smaller byte size of 2 bytes. When combined with aggregation, compression potentially yields a compressed size of up to 1 byte. In either case, bandwidth save is reached using compression and decompression codecs of varying data and bit rates. It is envisaged that an improvement in the performance of codecs would yield a better result in terms of enhancing results favourably in Voice over broadband networks. Keywords— VoIP Improvements, VoIP Optimization, Bandwidth Wastage, Bandwidth Utilization, Packet Header Reduction, Packet Header Compression, Header Aggregation, Silence Supression, Multiplexin, Delta-Multiplexing.