Abstract: A communication system couples a plurality of processing cores together, each having an associated register storing a virtual machine ID, which is inserted into requests sent by the respective processing core. A master circuit has associated a master interface circuit, wherein the master interface circuit has associated register for storing a second virtual machine ID, which is inserted into requests sent by the master circuit. A slave circuit has associated a slave interface circuit configured to selectively forward read or write requests addressed to an address sub-range. The slave interface circuit has associated a third register storing a third virtual machine ID associated with the address sub-range and is configured to receive a request addressed to the address sub-range, extract from the request a virtual machine ID, determine whether the extracted virtual machine ID corresponds to the third virtual machine ID, and then either forwards or rejects the request.