Thanks for reply

I want to know that how to implement this:

I am having some frame object in queue. I just want to implement simulation of dropping of frame from the queue while sending from sender to reciever, usisng the concept of cubbyhole as in link provided by you.
If sender doesnot get the acknowledgement for the frame then it will again send the frame back.

2. I want to implement simulation of the timeout of acknowledgement which is sent by reciever when it gets the frame from the common class like cubbyhole.
The schema at present is Sender takes tha packet from queue which is initialised in constructor and then assign the frame to commonclass. this common claas is the temporary reciepient of frame. then rciever get the frame from common class and then it send it send teh acknowledgement for the frame.
If sender doesnot get the ack for fram in timeperiod then it will again send back the frame to the reciever thru commonclass.


I want to know that how to easily simulate reciever acknowledgement sending timeout and dropping of frame sent by sender?


Sandeep