doi:10.1016/j.peva.2004.06.003
Copyright © 2004 Elsevier B.V. All rights reserved.
Call–burst blocking of ON–OFF traffic sources with retrials under the complete sharing policy
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Ioannis D. Moscholios, Michael D. Logothetis
,
and George K. Kokkinakis
Wire Communications Laboratory, Department of Electrical and Computer Engineering, University of Patras, 26500 Patras, Greece
Received 17 October 2003;
revised 18 June 2004.
Available online 11 September 2004.
Abstract
In this paper we calculate both call and burst blocking probabilities of ON–OFF traffic sources with retrials. Calls of service-classes arrive to a single link according to a Poisson process and compete for the available link bandwidth under the complete sharing policy. Blocked calls may immediately retry one or more times to enter the system, with reduced bandwidth and increased mean service time requirements. Call blocking occurs when a call cannot enter the system with its last bandwidth requirement, due to lack of bandwidth. Accepted calls enter the system via state ON and may alternate between states ON and OFF, or remain always in state ON. When a call is transferred to state OFF it releases the bandwidth held in state ON, so that this bandwidth becomes available to new arriving calls. When a call tries to return to state ON, it re-requests its bandwidth. If it is available a new ON-period (burst) begins. Otherwise burst blocking occurs and the call remains in state OFF. The proposed ON–OFF retry models do not have a product form solution and therefore the calculation of call and burst blocking probability is based on approximate formulas. The formulas we propose for the call blocking probabilities are recursive, whereas for the burst blocking probabilities are robust. Simulation results validate our analytical methodology. For further evaluation, the results of the ON–OFF retry models are compared with those of the ON–OFF model without retrials. We also discuss the extension of the proposed formulas in the case of a fixed-routing network.
Keywords: ON–OFF model; Call blocking; Burst blocking; Probability; Recurrent formula; Retrials; Loss model
Fig. 1. The service model of ON–OFF calls.
Fig. 2. The mechanisms of call and burst blocking in the ON–OFF model.
Fig. 3. The mechanisms of call and burst blocking in the ON–OFF retry model.
Fig. 4. Total link utilization for all models when C = C*.
Fig. 5. Average number of first service-class calls with b1 = 12, in state ON, for all models when C = C*.
Fig. 6. Average number of first service-class calls with b1 = 12, in state OFF, for all models when C = C*.
Fig. 7. Total link utilization for all models when C < C*.
Fig. 8. Average number of first service-class calls with b1 = 12, in state ON, for all models when C < C*.
Fig. 9. Average number of first service-class calls with b1 = 12, in state OFF, for all models when C < C*.
Fig. 10. Analytical and simulation BBP of the first service-class, when C < C*.
Fig. 11. Analytical and simulation BBP of the second service-class, when C < C*.
Table 1.
Analytical and simulation BBP results

Table 2.
Analytical CBP results when C = C* = 46 b.u.

Table 3.
Simulation CBP results when C = C* = 46 b.u

Table 4.
Analytical results for the real and fictitious link utilization when C = C* = 46 b.u.

Table 5.
Simulation results for the real and fictitious link utilization when C = C* = 46 b.u.

Table 6.
Analytical results for the average number of first service-class calls with other than b1 = 12 when C = C* = 46 b.u.

Table 7.
Simulation results for the average number of first service-class calls with other than b1 = 12 when C = C* = 46 b.u.

Table 8.
Analytical results for the average number of second service-class calls when C = C* = 46 b.u.

Table 9.
Simulation results for the average number of second service-class calls when C = C*= 46 b.u

Table 10.
Analytical CBP results when C = 46 and C* = 51 b.u.

Table 11.
Simulation CBP results when C = 46 and C* = 51 b.u.

Table 12.
Analytical results for the real and fictitious link utilization when C = 46 and C* = 51 b.u.

Table 13.
Simulation results for the real and fictitious link utilization when C = 46 and C* = 51 b.u.

Table 14.
Analytical results for the average number of first service-class calls with other than b1 = 12, when C= 46 and C* = 51 b.u.

Table 15.
Simulation results for the average number of first service-class calls with other than b1 = 12, when C=46 and C* = 51 b.u.

Table 16.
Analytical results for the average number of second service-class calls when C = 46 and C* = 51 b.u.

Table 17.
Simulation results for the average number of second service-class calls when C = 46 and C* = 51 b.u.

Part of this work appeared in the Proceedings of the 18th International Teletraffic Congress (ITC), Berlin, Germany, 31 August–5 September 2003.

Corresponding author. Tel.: +30 2610 996433; fax: +30 2610 991855.