ic stream 2[Ive04] Following gives an example of such a scenario. There are two traffic streams. The resource requirement for stream 1 is 1 bandwidth unit, and for stream 2 it is 3 bandwidth units. The total bandwidth in the system is 10 bandwidth units. Thus, N1 equals to 10 (=10 units/1 unit) and N2 equals to 3 (=10 units/3 units). The offered traffic of stream 1 A1 is 5 Erlang, and the offered traffic of stream 2 A2 is 1 Erlang. It is assumed that the service rate is equal to 1. Figure 6.6 illustrates the two-dimensional state transition diagram and Figure 6.7 shows the calculated state probabilities p(i,j). Traffic stream 1 Figure 6.6: Two-dimensional state transition diagram for a loss system with class limitations: (n1 =10, A1=5, 1=1); (n2 =3, A2=1, 1) 6.2 Dimensioning for Circuit-Switched Traffic number of connections (stream 1) number of connections (stream 2) Figure 6.7: State Probability of two-dimensional Erlang-B formula with class limitations: (n1 =10,11=5, u1=1); ( (n2 =3, A2=1, u2=1) The exact value of probability of each state p(i,j) is given in Table 6.1. p(i,j) 0.00054 0.0027 0.0016 0.0081 0.020 0.034 0.042 0.0032 0.016 0.040 0.067 0.084 0.084 0.070 0.050 0.0032 0.016 0.040 0.067 0.084 0.084 0.070 0.050 0.031 0.017 0.009 Table 6.1: State probabilities of two-dimensional Erlang-B formula with class limitations: (n1 =10,A/=5, 11=1); (n2 =3, A2=1, 1) In this example, the blocking probability for traffic stream 1 is 0.1038 and for traffic stream 2 is 0.3618, respectively, as calculated below. )=p(i+j=10)=p(10,0)+p(7,1)+p(4,2) = = = + p(3,1) = 0.1038 pb(2)=p(i+j=10)+p(i+j=9)+p(i+j=8)=0.3618 6.2.3 Iub Dimensioning with the Erlang-B Formula The job of dimensioning is to determine the necessary bandwidth or the required number of channels on the lub interface to accommodate the given offered traffic with a guaranteed QoS requirement. The following presents the detailed approach to apply the analytical models for the lub dimensioning. For dimensioning with a fixed blocking probability, as introduced in s