There is a issue with a patch on 4.5 that will cause SNMP MIB queries to not get a respones. Nortel recomends removing mplr26697 then INI to restart SNMP task. Following is cut and pasted from Nortel alert 2009009320 that was issued on 2/11
Background: The alert is to communicate issues experienced when using MPLR26697 on CS 1000 Release 4.5 systems.
Analysis: Patch I.D.: MPLR26697 Title: INI after BERR0705 in task "Snmpd" TM server disabled M3904 Set
MPLR26697 was issued to address a problem that resulted in a warmstart (INI) of the Call Server when specific maintenance tasks were performed via Telephony Manager(TM). This issue was reported from a single site and is considered to be relatively infrequent.
Software Impact: 4.50W
System Impact: CPT, CPP, CPP4, (SSC changed from LTD to OBE)
MPLR26697 was set to GEN Released status and delivered in the CS 1000 Release 4.50W DepLists (CPP, CPT, CPPIV) as of October 6th, 2008.
Problem Description: A recent issue has been detected with MPLR26697 in that it can block SNMP communication with the Call Server. The symptom is that SNMP MIB queries will not get a response. This issue would impact any NMS system attempting to communicate with the system, Telephony Manager operations, and NetIQ operations, where MPLR26697 is enabled.
Recommendations: It is recommended that MPLR26697 be removed to ensure above issue is not experienced. After MPLR26697 is taken out of service, it is necessary to initiatize (INI) the system.