I came across a practice question of true/false answer type . The statement is:
"A router has single network layer that will interact with 2 Data link layers" .
Ans:True (no explanation given)
DLL at router receives the incoming packet,pass it to N/W layer above,N/W layer finds the appropriate interface using routing table and forwards the packet to that interface . For this , the packet has to pass again through the DLL in the router .
My question is does the router have multiple DLLs(multiple NICs) with different mac addr(since Mac addr is based on NIC), each associated with their corresponding interface such that the receiving DLL passes the packet to NL above and during outgoing of same packet NL passes it to DLL of the appropiate interface which in turn passes it next hop?
Router has only single DLL that handles all interfaces on router,(DLL->NL->DLL) and the packet passes through the same DLL in router twice (during incoming and during outgoing)?can ignore the distinction shown in DLL in router in the image above?