VOICE -OVER -IP (VOIP) BANDWIDTH OPTIMIZATION: A SURVEY OF SCHEMES AND TECHNIQUES

Voice over Internet Protocol (VoIP) is a voice communication system that proffers the transmission and reception of audio (voice) signal and (or) data over the internet. One very crucial problem in a VoIP network is inefficient bandwidth utilization which in most case is caused by header overhead resulting from the attachment of a big (40 bytes) to small payloads (10 to 30 bytes). Given the need to reduce the amount of bandwidth being wasted or perhaps improving the utilization of bandwidth which ultimately could enhance network performance and VoIP quality of service, several schemes and techniques have been proposed. The improvement and (or) optimization of bandwidth can be achieved through; packet header reduction and defines a process of multiplexing and de-multiplexing packet headers to curb overflows. Silence suppression offer a technique of repressing the silent portions (packets) in a voice conversation using Voice Activity Detection algorithm, as a result, the transmission rate during the inactive periods of speech is reduced, and thus, the average transmission rate can be reduced. Voice/ Packet Header compression is considered the most productive of all the technique, and it presents an event whereby VoIP packets are compressed from the conventional 40 bytes of size to a smaller byte size (2 bytes in the best 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 optimizing bandwidth in a VoIP network.