When an Install package job involves large packages intended for a large number of clients, you can reduce the amount of data that has to be transmitted over the network by using multicast distribution.

With the standard method of job distribution (unicast distribution), adding more clients to the system means a proportional increase in the number of packets that must be sent from the higher system. However, with multicast distribution, you can distribute a job to a large number of designated clients by transferring the packets for just one job from the system one level above the client destinations. Reducing the volume of packet transmission in this way reduces both the load on the network and the time required to distribute the job.

In multicast distribution, the higher system sends the packets to a conceptual group called a multicast group. The packets are then forwarded to each client in that group. A multicast group is assigned a unique IP address, called the multicast address. At setup, you must set the same multicast address at the higher system and at each client member of that multicast group.

The following figure shows the differences between multicast and unicast distribution.

Figure 2-64 Differences between multicast and unicast distribution

To distribute a job to relatively few clients or when the package is small, it is better to use unicast distribution. Multicast distribution in such cases is actually the less efficient method.

To execute multicast distribution, from the Create Job dialog box and on the Job Distribution Attributes page, specify a distribution method when creating a job. For details about the system configuration and settings for executing multicast distribution, see 6.2 Settings for multicast distribution in the manual Description and Planning Guide.