Q4: (4points) Assume a network with 10 layers (the network layer is at level 3), each layer adds 10 bytes headers the Protocol Data Unit (PDU) and the time to prepare the encapsulation of a PDU is ( 0.1 mathrm{~ms} ) (millisecond) per layer. a) Calculate the time to send a message of size 1000 bytes from a host ( mathrm{A} ) to host ( mathrm{B} ) directly connected by a link of capacity ( 10 mathrm{Mbps} ) (Mega-bits per second) b) Same as in a) except that there is a router ( R ) between host ( A ) and host ( B(A ightarrow R ightarrow B) )

Q4: (4points) Assume a network with 10 layers (the network layer is at level 3), each layer adds 10 bytes headers the Protocol Data Unit (PDU) and the time to prepare the encapsulation of a PDU is 0.1ms (millisecond) per layer. a) Calculate the time to send a message of size 1000 bytes from a host A to host B directly connected by a link of capacity 10Mbps (Mega-bits per second) b) Same as in a) except that there is a router R between host A and host B(ARB)