CLIENT EGRESS MESSAGE DISCARD | Transmit Congestion

We use guaranteed messaging.
How to interpret Client Egress Message discard due to Transmit Congestion ?
Does these mean 3014 message got discarded ? If yes, Why the message should get discard in guaranteed messaging case !
Ideally it should spooled in Durable Queue.
****************************** Egress Discards ******************************
Total Egress Discards                          3014
 Transmit Congestion                          3014
 Compression Congestion                          0
 Elided                                  0
 Payload Could Not Be Formatted                      0
 Client Not Connected                           0
 TTL Exceeded                               0