This attribute specifies the gain in dB that is applied to data coming
from outside the network before it is transferred across the network.
It applies to voice, modem and fax traffic. For example, ingress gain
is applied to audio data coming from a PBX. If ingressAudioGain is
negative, a loss is applied.
ingressAudioGain and egressAudioGain are used in loss planning,
which is the configuration of the devices in a network to ensure that
the signal level from any point in the network to any other point is
correct.