In reply to Leo Lian:
I do not really understand your architecture. Especially why you need the queue. You have already 2 tlm fifos in your environment.
BTW, they should be in the scoreboard, then your structure becomes more easy.
The process should be like this:
When you receive a transaction on your output side you have to make a get on the input tlm, retrieving a tarnsaction from there and providing this to your ref model. The output of your ref model delivers you an transaction of the same type as the output transaction has and you can make a compare.
If you could provide me a complete example I could help in some more detail. Currently it is more guessing what I do.
If you don’t want to share your code here publically you can send me an email christoph@christoph-suehnel.de