Following the work in Disman has highlighted a number of difficulties with the basic technology of SNMP but as has been pointed out to me, most of those are Mib-related,not SNMP-the-protocol-related. But one that I see as SNMP (sensu stricto) and hence a possibility for this group, is the difficulty of identifying a PDU (as opposed to identifying a MIB object at which SNMP is very good). Sometimes it matters to know where information came from eg which PDU delivered the Notification so as to track/correlate/eliminate duplicates etc. As defined, SNMP does not seem to have any reliable way of doing so; any ideas? Tom Petch nwnetworks@dial.pipex.com