The Erlang B formula is useful for solving some of the exercises in the textbook

*Arrival Process:*Interarrival times are exponentially distributed. lambda = arrival rate (connections per unit of time)*Service Process:*Service times are exponentially distributed. mu = service rate (connections per unit of time)*Traffic Intensity:*rho = lambda/mu. Must be less than 1 for a stable system.- If all servers are busy upon arrival of a connection request, the request is Dropped.

- For a specified lambda, mu, and blocking probability, the calculator determines the number of servers that are needed to yield a blocking rate that is lower than or equal to the specified threshold
- For a specified lambda, mu, and number of servers, the calculator determines the blocking probability