Emulating links with WANem
If you're planning to publish applications on geographic links, it's very important to test how these applications perform. You'll learn later in this chapter how the optimizations work to improve the user experience.
Plan a complete User Acceptance Test (UAT) phase before going to production, if possible, with real users. In this section, you'll learn how to use an open source tool, WANem, to emulate a WAN link.
I usually prepare some test scenarios and ask users to give a score from 1 (bad) to 5 (good) for the user experience. The following table is an example of the feedback I got from a test session. It includes varying bandwidth (columns) and latency (rows), and is without any optimizations:
|
Time |
100 KB/s |
200 KB/s |
300 KB/s |
500 KB/s |
|---|---|---|---|---|
|
10 ms |
2 |
3 |
4 |
5 |
|
50 ms |
2 |
2 |
3 |
4 |
|
150 ms |
1 |
1 |
1 |
2 |
Installing
WANem is distributed as a bootable CD, based on Linux Knoppix. The operating system runs live from the CD, that is, you don't need to install it on the machine...