IBM® Tivoli® Monitoring assigns port numbers to each component in an installation to be used for communication with other components. Default well-known ports are reserved for major components such as monitoring servers and the portal server. For all other components, an algorithm calculates the listening port to reserve.
You might want to change or add to the default assignments under some conditions, for example, when the default port assigned to a monitoring agent has already been reserved by another application, or the portal server requires a second port number for communication through a firewall with Network Address Translation (NAT).