TIBCO SmartSockets Multicast

In addition to standard publish-subscribe with RTserver and RTclient, SmartSockets provides a multicast feature to further enhance the features and performance of SmartSockets. This option uses reliable multicast, taking full advantage of its bandwidth optimization properties. Multicast is an efficient way of routing a message to multiple recipients. The SmartSockets Multicast feature enables messages to be multicast to RTclients. SmartSockets Multicast uses the PGM protocol to route messages and a new RT process called RTgms to handle the message routing. There are new options for RTclients, and an extended logical connection name that allows the RTclient to connect to the RTgms process. To enable an RTclient to receive or send multicast messages, the RTclient simply connects to the RTgms process, instead of connecting to an RTserver.

To use multicast with SmartSockets, you must have purchased a separate license for the SmartSockets Multicast feature. Contact your TIBCO sales representative for more information. Any RTclients receiving multicast must be running with the SmartSockets Version 6.0 runtime libraries or higher. All RTservers should be at the same SmartSockets version level as the RTgms processes.

When Should I Use Multicast?

The SmartSockets applications that benefit most from multicast are those that distribute data among many network hosts simultaneously, rather than exchanging data with a few hosts at a time. Two models of data distribution exist: one-to-many and many-to-many. There are numerous examples of applications that implement these models.

A one-to-many application sends the same information to many receivers simultaneously. The data flow is one-way, from a single sender. An application that sends time-critical, real-time information, such as stock quotes, is an ideal example of a one-to-many application that benefits from multicast. Another example is a real-time satellite telemetry feed which must be distributed immediately to multiple workstations. Applications that send news and weather are also good examples of applications suitable for multicast. Any application that sends widely distributed information can benefit from multicast, even if the information is not needed as immediately as some of the previous examples. The analogous technical model is broadcast radio and television. The types of content these applications typically send and the schedule coordination requirements are similar.

A many-to-many application is one that shares information with a number of machines simultaneously. In other words, the data flow is bi-directional. Each receiver is also a sender. Each many-to-many application acts as a one-to-many application as it sends data and as a many-to-one application as it receives data.

Many SmartSockets applications involve one-to-many or many-to-many data distribution, where one or multiple sources are publishing the same information (messages) to multiple receivers. Examples can be found across industries:

Financial: communication of market data to traders, brokers and the general public

Manufacturing and process control: real-time collection, monitoring and distribution of sensor data from factory floors

Military or aerospace: real-time signal collection and distribution of data from satellites, radar, and integration and test stands

Telecommunications: real-time monitoring and control of network devices, and call and service routing

General: video and audio conferencing for remote meetings and teleconferencing

SmartSockets Multicast efficiently supports this one-to-many message distribution by enabling publishers to send a single copy of a message to multiple recipients who have subscribed to the same subject. This is more efficient than requiring the source to send an individual copy of a message to each subscriber, also called point-to-point unicast. In point-to-point unicast, the number of subscribers is limited by the bandwidth available to the publisher. SmartSockets Multicast is also more efficient than broadcasting one copy of the message to all nodes (broadcast) on the network, because many nodes may not want the message, and because broadcasts, in general, are limited to a single subnet.

SmartSockets Multicast is an efficient way to send messages when those messages are sent to many RTclients all receiving over the same subject on the same network. However, to use the PGM protocol, your network hardware, such as routers and switches, must support multicasting. For more information about what is required for a network that supports multicasting, contact TIBCO Product Support.