In queueing theory, a discipline within the mathematical theory of probability, a BCMP network is a class of queueing network for which a product-form equilibrium distribution exists. It is named after the authors of the paper where the network was first described: Baskett, Chandy, Muntz and Palacios. The theorem is a significant extension to a Jackson network allowing virtually arbitrary customer routing and service time distributions, subject to particular service disciplines.
Definition of a BCMP network
A network of m interconnected queues is known as a BCMP network if each of the queues is of one of the following four types:
- FCFS discipline where all customers have the same negative exponential service time distribution. The service rate can be state dependent, so write for the service rate when the queue length is j.
- Processor sharing queues
- Infinite server queues
- LCFS with pre-emptive resume (work is not lost)
Also, the following conditions must be met.
- external arrivals to node i (if any) form a Poisson process,
- a customer completing service at queue i will either move to some new queue j with (fixed) probability or leave the system with probability , which is non-zero for some subset of the queues.
For a BCMP network of m queues which is open, closed or mixed in which each queue is of type 1, 2, 3 or 4, the equilibrium state probabilities are given by
where C is a normalizing constant chosen to make the equilibrium state probabilities sum to 1 and represents the equilibrium distribution for queue i.
The original proof of the theorem was given by checking the independent balance equations were satisfied.
- Baskett, F.; Chandy, K. Mani; Muntz, R.R.; Palacios, F.G. (1975). "Open, closed and mixed networks of queues with different classes of customers". Journal of the ACM. 22 (2): 248–260. doi:10.1145/321879.321887.
- Harrison, J.M.; Williams, R.J. (1990). "On the Quasireversibility of a Multiclass Brownian Service Station". The Annals of Probability. Institute of Mathematical Statistics. 18 (3): 1249–1268. doi:10.1214/aop/1176990745. JSTOR 2244425.
- Sinclair, Bart. "BCMP Theorem". Connexions. Retrieved 2011-08-14.
- Harchol-Balter, M. (2012). "Networks with Time-Sharing (PS) Servers (BCMP)". Performance Modeling and Design of Computer Systems. p. 380. doi:10.1017/CBO9781139226424.029. ISBN 9781139226424.
- Harrison, P. G. (2004). "Reversed processes, product forms and a non-product form". Linear Algebra and its Applications. 386: 359–201. doi:10.1016/j.laa.2004.02.020.