Propagation delay is the time loss between when the signal is transmitted and when it is received.
Delay skew is the difference in propagation delay between any two pairs in the cable. This parameter is key on any application that utilizes multiple pairs for parallel transmission. The addendum includes measurement methods and allowed variability within a specific operating range of environmental conditions. This addendum adds definitions as well as requirements for bundled and hybrid cables. A bundled cable is a combination of two or more cables bound together to form one unit.