1) In Distance vector routing when there is any change in the link cost is it updated in the routing tables of the routers connected via that link immediately? or is it only done during the time when there will be a periodic update at which those routers send their old routing tables and then update the cost?
2) A scenario as follows: P is connected to Q and R both and Q is connected to T. At t=0 they exchange their routing tables P has its own routing table with cost of Q and R but when it gets routing table of R it figures out there is an shorter path via R to Q and hence it updates its distance to Q via R. Then it figures out T can be reached via Q now it will update T's distance with the updated distance of Q right? and if suppose Q was not updated by then den T's distance would have been updated with Q's old distance?
Any help highly appreciated..