 Amsterdam. Brockmeyer, E., Halstrom, H.L. and Jensen, A. (1948) The life and (5.71) works of A.K. Erlang, Academy of Technical Sciences, Copen- hagen. Gibbens, R.J. and Kelly, F.P. (1990) Dynamic routeing in fully (5.72) connected networks, IMA J. Math Control Inform, 7, pp. 77- Hui, Y.J. (1990) Switching and traffic theory for integrated broad- (5.73) band networks, Kluwer, Boston. Kelly, F.P. (1979) Reversibility and stochastic networks, Wiley, Chichester. The loss probability, L is then as in Equation 5.74 where B and Kelly, F.P. (1990), Routeing in circuit switched networks: optimiza- B2 are the link blocking probabilities for fresh and overflow traffics tion, shadow prices and decentralization, Adv. in Appl. Probab., respectively and are given by Equations 5.75 and 5.76. 20, pp. 112-144. (5.74) Key, P.B. and Whitehead, M.J. (1988), Cost effective use of net- works employing Dynamic Alternative Routeing. In Proc. 12th International Teletraffic Congress, Turin, North-Holland, Am- sterdam. (5.75) Key, P.B. and Cope, G.A. (1990) Distributed dynamic routeing (5.76) schemes, IEEE Communications Magazine, Advanced traffic control methods for circuit switched telecommunication net- i=C-r works, 28, (10), pp. 54-64. In the United States, AT&T has recently started implementing a Narenda, K.S. and Mars, P. (1983) The use of learning algorithms closely related dynamic routeing strategy called Real Time Network in telephone traffic routeing - A methodology, Automatica, 19 Routeing (RTNR) (see Ash, 1991). (5) pp. 495-502. Stacey, R.R. and Songhurst, D.J., (1987) Dynamic alternative rou- teing in the British Telecom trunk network, Int Switching Sym- 5.5 Bibliography posium, Phoenix. Ash, G.R., Cardwell, R.H. and Murray, R.P. (1981) Design and Wong, E.W.M. and Yum, T.S. (1990) Maximum free circuit routeing optimization of networks with dynamic routeing, Bell Syst Tech in circuit switched networks, Proc. IEEE Infocom '90, IEEE J, 60, (8), pp. 1787-1820. Computer Society Press, pp. 934-937. Electromagnetic waves J H Causebro