I can only share what we are doing here(a large delivery center in a large bank managed by the blue giant.)
We have strictly separated envs for development, SIT and UAT and there are rigid processes control the promotions from dev to SIT to UAT.
People(testers, developers, managers and whoever) are sitting in dev env(scattered in a few floors.) And the rest(SIT, UAT) are in a big server room).
Our dozens of testers are doing manual tests and functional automations from their desks in dev env, sometimes from overseas, and I don't see any problem with that.
I have set up an isolated env in the server room for the load test. Complete separated VLAN and machines only for load testing purposes. The load generators are directly access the UAT env via only firewalls, routers. All load test projects are running here. Once established, you don't need to change anything. And I am quite happy with this set up in the past one year.
Can anybody explain the process of setting up a testing environment from scratch? My group has to test a real time trading platform, and have 5 testers. I would like to do both manual and automated testing using probably winrunner, loadrunner and testdirector for repository. Thanks.