Before you can test the performance
of TCP/IP socket-based applications, set up your test environment
and incorporate these guidelines to produce reliable performance tests.
Limitations
You
can use this extension to test applications that run in a client-server
model, where the test simulates multiple clients that connect to one
or several servers. Other models, such as peer-to-peer networks, are
not supported.
Performance
When
you deploy performance tests, use a relevant number of virtual users
on a given computer is important. For example, if you deploy too many
virtual users on a single computer, the results will reflect more
the load of the test computer than the load of the server.
For best results with performance tests on an average test computer
with a 1 GHz processor and 1 GB of RAM, do not exceed 1000 concurrent
virtual users.
If you exceed the number of virtual users that
a single test computer can run, the measured performance of the server
will be affected by the performance of the test computer, which will
invalidate the final results.
When editing a schedule for long
performance tests, use these guidelines:
- In the schedule editor, reduce the Test log level to None.
- In the schedule editor, set the Statistics sample interval to approximately 1/60 of the run time, for example 12 minutes for
an estimated 12-hour session.
- When possible, use loops inside test suites rather than loops
in the schedule. Using loops inside test suites avoids connection
problems that might occur over long duration tests and emphasizes
measurement of the send and receive activity rather than connection
and close activity.
SSL/TLS Authentication
Socket tests support simple or strong Secure Sockets Layer (SSL)
or Transport Layer Security (TLS) authentication mechanisms, also
called server authentication and client authentication.
For
server authentication, the client must determine whether the server
can be trusted. When you are recording or running a socket test with
a proxy recorder, the proxy recorder sits between the server and the
client. Therefore, you must "trick" the client application into behaving
as though the proxy recorder is the certified server by performing
either one of the following actions:
- Configure the SSL or TLS settings of the recorder proxy to authenticate
itself as the actual server to the client and as the client to the
service. This means that you must supply the recording proxy with
the adequate certificates.
- Configure a managed client (an external client application) to
accept the proxy recorder as though it were the certified server.
The recording wizard provides a link to download and import an IBM® Rational® Performance Testercertificate into the client application.
For client authentication, the server must authenticate
the test client according to its root authority. Therefore, you must
provide the client certificate that is expected by the server to authenticate
the proxy recorder or the test agent as a certified client.
See Digital certificates overview for more information about managing digital
certificates.