This attribute counts the number of frames which have
retransmission time-out.
If packets from Vc into the subnet are discarded by the subnet, the
source Vc will not receive any acknowledgment. The retransmission
timer then expires and packets will be retransmitted again. Note that
the Vc idle probe may be retransmitted and is included in this count.
This statistics does not show the distribution of how many times
packets are retransmitted (e.g. first retransmission results in
successful packet forwarding).