Hello!
I am Network Engineer with big experience of making monitoring systems based on SNMP/j-flow, custom scripts work.
i have worked almost all lines of Cisco, Juniper routers, switches and security devices.
I have used cacti (and mrtg before) from scratch for city wide broadband ISP and have made monitoring everything for it:
Routers, switches: monitoring interface load, errors, cpu used, memory, temretature, number of users, parameters of NAT operation and so on.
Servers: interface load, cpu load, memory used, disk usage, number of processes, for DNS for example - various analysis on requests (number, rate, correlation between parameters),...
I know very well internals of tools, which are bricks of cacti/xrtg - rrdtool, php, snmp protocols, know operation of SNMP (v1,2,3) for networks. I've written my own system with rrdtool for small ISP (look topology at my portfolio) based of these tools
Also i can help if you need additional monitoring tools - syslog, netflow/j-flow monitoring, automatition scripts for monitoring/configuration. Can make it on separate web page for example.
To make your task it is better if you give ssh/web access to your system.
I will make all needed documentation/explanations.
best regards,
Stanislav