4) Host A is connected to router R1 and host B is connected to router R2. Router Rl is connected to router R2. A TCP message contains 940 bytes of data and 20 bytes of TCP header are passed to the IP code at the host A for delivery to host B. IP layer will append 20 bytes. Assume that router RI supports a maximum transfer Unit (MTU) of 1024 bytes including 16 bytes frame header and router R2 has MTU if 512 bytes including 8 frame header. a. With the aid of diagram show the size of IP fragments received by router R1 and R2 b. Determine the number of bytes received by host B at IP layer