Consider the following design problem concerning implementation of virtual- circut service. If virtual circuits are used internal to the subnet, each data packet must have a 3-byte header and each router must tie up 8 bytes of storage for circuit identification. If datagrams are used internally, 15 byte headers are needed but no router table space is required. Transmission capability costs 1 cent per $10^6$ bytes, per hop. Very fast router memory can be purchased for 1 cent per byte and is depreciated over two years, assuming a 40 hour business week. The statistically average runs for 1000 sec. in which time 200 packets are transmitted. The mean packet requires four hops. Which implementation is cheaper and why?