This attribute counts the total number of cells containing silence
data received from the interface which was not forwarded into the
network, thus saving bandwidth. A channel may go into silence due
to the operation of the silence suppression feature 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.