Assume that source S and destination D are connected through two intermediate routers labeled R.

Question

 Determine how many times each packet has to visit the network layer and the data link layer during a transmission from S to D.

Answer 1

in source it is 1 data link and 1 network .. now as routers are in network layer so 

in router1:

 at first it goes to network layer like physical->DLL->network (then again comes to physical like)->DLL->physical 

Router2:Phhysical->DLL->network->Dll->physical

Destination:

Physical->DLL->NEtwork->TCP->Application

in both routers after computation in Network layer it is coming back to physical again ..the reason is signals can only be transmitted with physical layer

So Network Layer=4 Visit

DLL=6 Visit

I think it was asked in previous GATE question... But i provided the explanation as that is not there

Comments

I have provided the explanation there also.. Arjun sir or any admin can close this question as duplicate