I hope this is the right 'subforum' to post my question, if not, sorry, I was not sure... What kind of model is airport simulation of a queue (planes land and take off) with one runway (one server only). I am sure about the first and the last parameter but not about the 'middle': M/(const)/1? What does 'distribution of service' exactly mean? When is it constant, i.e. can it be constant in this case? Thanks for your help.