The Cost of Asymmetry and Asynchronicity

We have considered the additional cost implications of asymmetric traffic. Avoice network
is a symmetric network; the uplink and downlink are balanced. Arich media network
is by nature asymmetric, since asynchronous traffic is by its nature asymmetric.
The asymmetry is not fixed but constantly varying as the offered traffic rate increases
and decreases on a (10-ms) frame-by-frame basis in either direction. We see the symptoms
of this in the radio physical layer where the allocation of code domain power is
constantly changing on the uplink and downlink to accommodate constantly changing
bidirectional user data rates.
Similarly, the allocation of network resources will be constantly changing. It will be
statistically rare for the uplink and downlink to be balanced—another argument for
using ATM (or equivalent packet-switching capabilities).