Scope of TCP and UDP in bigfix

what TCP and UDP will do in BigFix? what is their scope of work?

https://www.ibm.com/developerworks/community/wikis/home#!/wiki/Tivoli%20Endpoint%20Manager/page/Network%20Traffic%20Guide

Most traffic in BigFix is TCP. When there is a new Fixlet or Action available, the Server will use UDP to notify it’s registered clients about it. If the Notifies Client is a Relay, it will repeat the notification process until all clients are notifed.

UDP is only used from the last relay to the endpoint. Relay to Relay (that includes the server) is done via TCP