Multicast is a messaging model that allows the EMS server to send messages to multiple consumers simultaneously by broadcasting them over an existing network.
Bellow figure shows how using multicast can reduce the amount of bandwidth used to send a message. Where publish and subscribe messaging creates a copy of a published message for each message consumer,
multicast broadcasts the message only once. Multiple multicast daemons listening on the channel receive the same broadcast.
Configuring Multicast :
Multicast is configured in the EMS server configuration files. Configuration is a simple three-step process:
1. Enable multicast in the EMS server.
Enable the multicast parameter in the tibemsd.conf file.
2. Create multicast channels.
Create named channels in the channels.conf file.
3. Associate topics with channels.
In the topics.conf configuration file, add the channel property to the definitions of those topics you wish to be multicast.
1. Enable multicast in the EMS server.
Enable the multicast parameter in the tibemsd.conf file.
2. Create multicast channels.
Create named channels in the channels.conf file.
3. Associate topics with channels.
In the topics.conf configuration file, add the channel property to the definitions of those topics you wish to be multicast.
Note that a topic can be associated with only one multicast channel.
