3G uses both a circuit-switched mobile core
network and a packet network, while 4G is a
packet network. The 3G-324M protocol is used
to support real-time multimedia services over
wireless circuit-switched 3G networks. The circuit-
switched network provides a 64 kb/s circuitswitched
path, but published measurements [6]
with live 3G networks gives uplink speeds of
only 50 kb/s. As the current minimum upstreamdownstream
bandwidth required by a video chat
application is 128 kb/s, a circuit-switched mobile
core network is unsuitable for video chat.