Updation of config variable is not updated

Common_config is set in the test and get in all the lower components. One of the config variable im updating in sequence, for example common_config.rate = rate, the rate value changes for each testcase.
Since, the common_config.rate is able to access in source side but not in the sink.

Since, source can access the common_config but not in the sink. Why??

Is there any method to get access in sink also??