80 страниц. 2011 год. LAP Lambert Academic Publishing It focuses on the assessment of OSPF routing protocol in terms of its behaviour in the network while one of the neighbours in down state compared with performance of the same network and the same conditions with down state neighbour monitoring by SNMP using OPNET IT Guru Academic edition 9.1. we run two simulation experiments. While the first experiment will examine the performance of OSPF routing protocol with node in down state analysing the different performance criteria on medium scale network, the second experiment will indentify and analyse the performance with the exact topology and the same conditions down state neighbour. Furthermore, in the second experiment, SNMP as protocol is implemented to monitor the failure neighbour and to compare the results so as to arrive at whether or not this protocol is effective to use under such circumstances.