Methods for improved cable modem ranging in a data-over-cable system. One
method includes receiving a value that characterizes how equipment in the
network is configured. Using this characteristic value, a cable modem may
estimate loss in its upstream path from a measurement of a downstream
signal and thereby estimate its initial transmit level during ranging.
Launching at a proper initial transmit level may ensure that range
request messages arrive at the cable modem termination system with
sufficient strength to be detected and hence ameliorate ranging. Another
method collects difference between these estimated initial transmit
levels and the final transmit levels that succeeded in evoking a response
from the cable modem termination system. The collected differences are
analyzed and the result of the analysis is passed to cable modems to
adjust their estimated initial transmit levels. These methods may shorten
a cable modem's time for ranging and may decrease collisions on the
upstream path when many cable modems try to range simultaneously.