Often times you are faced with a problem that’s reported by your network monitoring solution, but you simply cannot identify the root cause. Based on NetFlow analysis you can isolate the flow(s) in question, maybe even look deeper into overall latency performance and configuration settings like QoS, but even with that there’s still just not enough information to determine the root cause. To be more specific, let’s say you have an end user who is reporting problems with a slow-moving application. You have exhausted your flow-based analysis and confirmed that overall latencies are excessive, but you can’t see why. So, what’s next? This is where packet payloads come in.
What Is a Payload?
In aerospace/military jargon, where the term originated, the payload is the carrying capacity of a particular delivery vehicle. For example, the payload of the space shuttle includes astronauts, their experiments, and equipment to be delivered to the space station. In networking, although the scale is quite different, a payload is very analogous. It is the data that is being carried within a packet or other transmission unit over the network. Simply put, the payload is the bits of meaningful data that get delivered to the end user sans the delivery data that makes an application work. Without payloads there is no useful information to communicate, kind of like sending empty envelopes via snail mail.