According to me: environment test need:
2. website server which need load test .
3. Client PCs
condition: server and client must to put in one place to to ensure the network is not affected by external major.
is this correct?
1. Server (APP and DB) : internal or External network just make sure you have access from where your trying to load the server, but placing in the different networks another parameter is network latency which has to be taken into account,
2. LGs(load generator) : both master and slave has to be in same network or that can also be in different networks, but if you go different network cost would be increased to set up.
its not about checking network bandwidth, just mentioning the point that has to be consider before setting up your environiment just make sure you have enough bandwidth, based on the size how much bandwidth it might require can be caliculated, so based on this factor you can, just make sure you have enough bandwidth before you start the load test. For these caliculation refer google