This attribute counts total cells containing silent modem or fax data
received from the interface which was not forwarded into the
network, thus saving bandwidth. A channel may go into silence due
to the silence Suppression feature (refer to the silenceSuppression
attribute) or for CAS channels when the ABCD signalling bits go
idle.
A cell contains 44 bytes of data from the DS0 channel (5.5 ms).
This flow is measured before compression is performed on the
channel.
This counter wraps to zero after reaching its maximum value.