Mailboxes and queues are couple of basic data constructs of system verilog language. Lets get to the definition of them: Queue: A Queue in system verilog function as the name suggests. But with a twist. Queue in system verilog is a list of similar elements. Queue is built on top of an array. Delcaration of a queue. < TYPE > < que_name >[ $ ]; Default Behaviour: The default size of the queue in system verilog is " Infinite ". The above declaration will create a que of infinite length. You can add elements to the que until your simulator crashes :) What if you want to create a queue of finite length. Just look at the declaration below: < TYPE > < que_name >[ $ :< LIMIT >]; The above declaration will create a queue of size " LIMIT+1 " Initializing queue with elements Accessing elements of a queue Methods in queue Inserting elements into queue Reoving elements from queue http://www.project-veripage.com/queue_1.ph