See also a related post: description of a substantial TeamCity setup.
Network Traffic between the Server and the Agents
The traffic mostly depends on the settings as some those include transferring binaries between the agent and the server.
The most important flows of traffic between the agent and the server are:
- agent retrieves commands form the server: these are typically build start tasks which basically include a dump of the build configuration settings and full set of build parameters. The latter can be large (e.g. megabytes) in case of large build chain. The parameters can be reviewed on the build's Parameters tab;
- agent periodically sends current status data to the server (this includes all the agents parameters which can be reviewed on the Agent's "Agent Parameters" tab);
- during the build, agent sends the build log messages and parameters data back to the server. These can be reviewed on the Build Log and Parameters tabs of the build;
- (when server-side checkout mode is used) agent downloads the sources before the build (full or incremental patch) from the server;
- (when artifact dependency is configured) agent downloads build artifacts from other builds form the server before starting a build;
- (when artifacts are configured for a build) agent uploads build artifacts to the server;
- some runners (like coverage or code analysis) include automatic uploading of their results' reports to the server.
Configuring TeamCity Server for Performance