  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
