Terminology – Difference Between Frame, Packet, and Payload

The terms do get thrown about quite a bit and the definition is a bit of a murky issue as they can be used in several ways.

I would say that generally a leased line is a line you are paying someone else for use. For instance, you can string your own copper and establish your own T1/T3 service between buildings. However, you could also pay someone to provide and maintain that line. Often leased lines have a SLA associated with them.

A dedicated line would be a line that is dedicated to you/your company. For instance, in an office building, you may not have a dedicated line. You may have a PRI that comes into the building and provides service to multiple organizations. Often this is cheaper because the telecommunications company doesn't need as many lines going into the building and has fewer to maintain.

Latency is the amount of time it takes a packet of data to leave your computer and receive a response back from the end point. That is why this is measure in time. This is key for time sensitive applications like VoIP and video conferencing.

Bandwidth/data rate is the amount of data (bits) you can upload or download in a given time (seconds). This is key for downloads and uploads (i.e. video streaming for Hulu, Netflix, etc). It is also important in video conferencing as you're sending/receiving a lot of video (bandwidth) and the audio portion needs to be in near real time (latency).

Ping is sending packets using ICMP and measuring the time it takes until you receive an echo-reply from the end point. It is not sending a lot of data and would not give any accurate information regarding bandwidth.

Something like iperf may be used to measure bandwidth by sending a lot of data to the end point which also would be running perf.

You can have high latency (slow round trip time for packets) but still have a lot of bandwidth. Satellite service is one example.