—Anotationusedtocharacterizequeueingsystems.—Originally, "A/S/c", with "A" thearrivalprocess, "S" thedistributionofservicetimerequired, and "c" thenumberofservers.—Extended, "A/S/c/K/N/D", theabove, plus "K" thenumberofplacesinthequeue, "N" thesizeofthepopulation, and "D" theservicediscipline.