Grade of Service of Direct Traffic Mixed with Store-and-Forward Traffic

Direct traffic is a user-to-user service (generally voice) requiring a connection to be established promptly on demand. Store-and-forward (S/F) traffic, on the other hand, is stored at or near the originator's location and is later sent to its destination, either directly or through further intermediate storage. If S / F traffic is sent only when the direct traffic load is light, large amounts of S / F traffic can be accommodated with very slight degradation of direct traffic service. This can be especially important in a long-haul communication system where the trunk group cross sections (number of trunks in a group) are small. Such trunk groups are notoriously inefficient if used only for direct traffic, but they have a substantial ability to handle additional S / F traffic. * T h i s work has been carried out under U. S. Army Signal Corps C o n t r a c t DA-36-039-SC-7880(i. f I . T . T Federal Laboratories, N u t l e y , N. J., (work performed for Bell T e l e phone Laboratories). Present affiliation, General Electric C o m p a n y . 1415