In reply to Er. Shipra:
As mentioned by Chris, please show the code where you have tried the inter-component communication. A simple example can be seen from here.
In your code, you need to do this:
// In high level env
mailbox #(int) mbx = new();
master_ag.mbx = this.mbx;
slave_ag.mbx = this.mbx;
// If Master
mbx.put(rd_next_addr);
// If Slave
mbx.get(rd_next_addr); // mbx.try_get(rd_next_addr);
Or you can go with uvm_queue singleton approach where UVM has created everything for the user.