The following figure shows the standard system configuration for implementing multicast distribution and the packet flow.

Figure 6-15 Standard system configuration for implementing multicast distribution and packet flow

The managing server, higher system to which the clients are connected, and the clients themselves must all be running the Windows version of JP1/Software Distribution 06-71 or later.

You must create a multicast group for each higher system to which clients are connected, and you must assign a unique multicast address to each multicast group. The description below is keyed to the numbers shown in the example system shown in Figure 6-15. Nos. 1 and 2 are system configuration settings; Nos. 3 and 4 are the packet flow when the job is executed.

1. Set the group of clients connected to relay system A to be multicast group A, and the group connected to relay system B to be multicast group B. Specify multicast address 239.255.0.1 for the clients in multicast group A, and 239.255.0.2 for the clients in multicast group B.
2. Specify the multicast address of multicast group A (239.255.0.1) for relay system A, and the multicast address of multicast group B (239.255.0.2) for relay system B.
   Using multicast distribution, relay system A can now distribute jobs to the clients in multicast group A, and relay system B can now distribute jobs to the clients in multicast group B.
   
3. At the managing server, create a job with multicast distribution specified, and then execute that job.
   The managing server sends the packets for the job to each of the relay systems. In this example, two relay systems are connected to the managing server, so packets equivalent to two jobs are sent (unicast distribution). The jobs are sent by unicast distribution to relay systems A and B.
   
4. Relay systems A and B each send the packets for just one job, regardless of the number of clients. The packets for one job flow on the common routes to each client (multicast distribution).

In the same system configuration, if the job were distributed using unicast distribution, the number of job packets flowing from the higher systems to which the clients are connected to the destination clients would be multiplied by the number of clients. Therefore, three times the number of packets would be sent from relay systems A and B along the routes shown in 4.

Jobs can be distributed using multicast distribution even in a configuration in which the clients are connected directly to the managing server. In this case, the multicast address of the multicast group to which the job is to be distributed must be specified at the managing server.

Multicast distribution requires the Windows version of JP1/Software Distribution 06-71 or later. This section explains how jobs are distributed when the configuration of the systems to which the jobs are to be distributed includes a version of JP1/Software Distribution that does not support multicast distribution (Windows version of JP1/Software Distribution 06-53 or earlier or the UNIX version of JP1/Software Distribution).

If a higher system to which the clients are connected is running a version that does not support multicast distribution, multicast distribution cannot be used between that system and its clients. In such a case, even if a job for which multicast distribution is specified is sent from the managing server, it is distributed by unicast distribution.

If a client is running a version that does not support multicast distribution, the job is sent to that client by unicast distribution. The following figure shows the packet flow when the system configuration includes a client that does not support multicast distribution.

Figure 6-16 When a client does not support multicast distribution

The following explains what occurs when jobs with multicast distribution specified are sent from the managing server in an environment in which there are several relay managers/systems (relay managers or relay systems) arranged in a hierarchy.

When relay managers/systems are arranged hierarchically and a relay manager/system above the higher system to which the clients are connected does not support multicast distribution, jobs are distributed by unicast distribution to the systems below it. However, if the relay manager/system above the higher system to which the clients are connected is one of the following, jobs can be distributed using multicast distribution from the lower relay system to the clients:

• Windows version JP1/Software Distribution SubManager 06-00 to 06-53 or later
• UNIX version of JP1/Software Distribution SubManager or the UNIX version of JP1/Software Distribution Client (relay system) 09-00 or later

The following figure shows the flow when jobs are distributed by multicast distribution between the lower relay system and clients in a configuration that includes multiple relay manager/systems arranged hierarchically.

Figure 6-17 Hierarchical relay managers/systems (multicast distribution on lower routes only)