Setting PGM Options

The PGM options used for RTclients and RTgms processes are different from the other SmartSockets options. You can use the defaults for these options if the default PGM configuration works for you. If you use the defaults, you do not need to change or set any values because there are no required options.

However, if you need to change a value for either your RTclient or RTgms process, you must create a multicast command file, mcast.cm, for the RT process. The multicast command file is treated just like any startup command file, with the exception that there is only a system-level mcast.cm file. There are no user-level or local-level mcast.cm files. This system-level mcast.cm file is located in the SmartSockets standard directory or partitioned dataset:

In your mcast.cm file, set the PGM options you want to change using setopt. Here is a sample mcast.cm file:

setopt  pgm_source_max_trans_rate 5000000  /* change max trans rate to 5 meg  
*/ 
setopt  pgm_udp_encapsulation       1      /* enable UDP encapsulation        */ 

If you want to share an mcast.cm file among several RTgms or RTclient processes, you can specify which mcast.cm file they should use in the mcastopts.cm file, also located in the standard directory. The mcastopts.cm file contains one option, mcast_cm_file.

For certain PGM options, you can set them dynamically for a particular group channel using the T_MT_GRP_ADMIN_SET_PGM_OPTIONS message. Currently, only the Pgm_Source_Max_Trans_Rate option can be set using this message. For more information, see RTgms Options.