= BOINC network communication overview =

The BOINC core client communicates with several servers in the course of getting work and returning results. All communication uses HTTPS or HTTP on ports 443 or 80, so client can function through firewalls and proxies.

[[Image(comm.png)]]

 * The client downloads the page from project's [ServerComponents master URL]. From XML tags embedded in this page, it obtains a list of domain names of '''schedulers'''.
 * The client exchanges [RpcProtocol request and reply messages] with a scheduling server. The reply message contains, among other things, descriptions of work to be performed, and lists of URLs of the input and output files of that work.
 * The client downloads files (application programs and data files) from one or more '''download data servers'''. This uses standard HTTP GET requests, perhaps with `Range` commands to resume incomplete transfers.
 * After the computation is complete, the client uploads the result files. This uses a [FileUpload BOINC-specific protocol] that protects against DOS attacks on data servers.
 * The client then contacts a scheduling server again, reporting the completed work and requesting more work.