| Optic networks based on SDH are the backbone of the communication transport networks,which carry services greatly varing in speed,format,bursting frequency, latency and error to-lerance. Growing deployed circumstances and service varieties are challenging the OAM(Operation,Administration and Maintenance) of SDH networks. This dissertation comes froma simulation platform aimming at building an environment which can accomplish normal op-eration such as coping with types of SDH frames and abnormal operation such as insertingalarm rooted from SDH standards. The platform can be applied to impove technical abilitylike OAM skills,network optimation of SDH and academic use, in which stations functionlike SDH part of a ZTE multiple service transport platform.As for normal operation part, the design of cross-connect system is the focus.It beginswith describing characteristics of synchronous time division signal,combines with boardstructures of a SDH station and fulfil the task of rearranging VC-4,VC-12including tributaryand line part. We address a simple but efficient way for high-level spatial divisioncross-connect.In lower-level cross-connect part,a CFTT method is introduced for betterswitching throughput.CFTT adopts pairing input and output port first according to serviceconfiguration then using a switching frame test the connect relation.This essay illustrates fea-sibility of the scheme through inner collision and switching capacity simulation with outcomeattached.At last three different switching capacity left in reading-writing CFTT is compared.Alarm and adaptive ability like code rate and pointer justification account for two parts ofabnormal operation simulation. Over20main communication alarms which have been used inthe stimulation platform construction are analyzed as to their driving and suppressing rela-tions. The demonstration of SDH adaptive ability is accomplished through changes of show-ing overhead bytes in the simulation using corresponding units as abnormal insertion point. |
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