A traffic engineering model that assumes that an offered call is cleared immediately, with no queuing. In other words, Erlang B assumes that a call encountering blockage will not appear again. Either the caller will hang up and not attempt to place the call again, or the call will automatically be routed over another circuit if one exists, even if the use of that circuit is more expensive. See also Erlang, Erlang C, Equivalent Queue Extended Erlang B, Extended Erlang B, GoS, Poisson distribution, traffic, and traffic engineering.