A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology,1992

All existing routing schemes of circuit switched telecommunication network perform routing decisions at the call set up time. Once a call has been set up the call route through the network remains fixed for the duration of the call. Reconfigurable Routing (RR) scheme has the capability to reroute an established call. This research is an investigation by computer simulation of different RR schemes for a circuit switched PSTN/ISDN trunk network. The main objective of this simulation is to investigate the potential improvemen t of GOS obtainable when compared with existing routing schemes. The resilience of a RR scheme on different types of network perturbation ( e.g., unbalanced overload or link failure condition) is also investigated. Implementation issues such as error performance under error probability due to time delay difference between the old and the new routes, the extra loading to the signalling network and signalling processor due to the call reconfiguration are estimated. Simulation results show that RR schemes improve GOS significantly, exhibit better performance under overload conditions and.:provide comparable performance under link failure conditions when compared with existing routing schemes. Signalling network and processor suffer extra loading due to reconfiguration but this is not significant when compared with the over all signalling load. :Error performance restricts the use of RR schemes to an upper limit on offered traffic and a lower limit on call holqing time