[inigyou]

Circuit switching has latency and QoS advantages, but it's definitely not worth the cost for most use cases.

Interestingly, TDM carriers have a latency of approximately one bit per hop and jitter less than that, while any kind of packetized voice such as VoIP has a latency of at least one packet worth of audio, plus one to several packet transmission times per hop, and jitter of several packet transmission times, and packet drop on top of all that. We've actually made quality worse in the name of fitting more services down the same wire, which isn't necessarily bad but it's something to think about.