I work for a large organization where the network team is in some disarray (key people left/fired, etc.). My team is responsible for the performance of various client/server applications which of course utilize the network. We often receive performance complaints from application customers ("xxx app is slow").
When we receive these complaints, we check our servers for issues. Sometimes we'll restart them and so forth. If we can't find any issues there, our focus turns to the network (since these are client/server apps). We used to have competent network engineers who could inspect/measure traffic between the clients/servers, but don't have that luxury anymore.
What are some simple performance monitoring approaches we could take to give us a quick--historically contextual--answer around whether the network is misbehaving right now? For example: I can imagine a script or tool which might copy a 1MB file from point A to point B every 30 minutes and record the transfer time. Perhaps it would present the most recent transfer time vs. the last 5 days vs. the last 30 days vs. the last year.
Keep in mind my team does not have access to the network infrastructure itself (no SNMP, netflow, perfmon, etc.).