User Manual

Table Of Contents
RF-Baton! Transmitter Controller Installation and Operation Maintenance
June 1999 6880497G01-B 6-43
Assigning an RF-B! Transmitter Controller to a Multicast Group
Each RF-B! transmitter controller must have an individual (unicast) IP address to process the
traffic. In addition, each RF-B! transmitter controller can be part of up-to 16 multicast groups.
This means that the RF-B! can have 1 unicast and up-to 16 multicast IP addresses for a total of
17 IP addresses. (The multicast address is a Class D IP address.) The RF-B! transmitter
controller joins a multicast group and registers with the routers using Internet Group
Management Protocol (IGMP). A group can consist of any number of RF-B! transmitter
controllers.
Multicasting allows an RF-C! controller to send one packet for each group rather than having
to send individual packets to each RF-B! transmitter controller. This reduces the amount of
traffic the controller and network have to handle.The network then routes the packets to the
members of the group. The router queries the RF-B! transmitter controllers for group
membership on a regular basis (usually once a minute), and the transmitter controllers
respond with the group identifiers (IDs).