Overview Networks are used to interconnect many devices We have checked with local area Networks Now, wide area networks Since the invention of the telephone, circuit switching has been the dominant technology for voice communications Since 1970, packet switching has evolved substantially for digital data communications. It was designed to provide a more efficient faclity than circuit switching for bursty data traffic. Two types of packet switching Datagram(such as todays Internet Virtual circuit such as Frame Relay aTm)2 Overview • Networks are used to interconnect many devices. • We have checked with Local Area Networks. • Now, wide area networks — Since the invention of the telephone, circuit switching has been the dominant technology for voice communications. — Since 1970, packet switching has evolved substantially for digital data communications. It was designed to provide a more efficient facility than circuit switching for bursty data traffic. • Two types of packet switching: – Datagram (such as today’s Internet) – Virtual circuit (such as Frame Relay, ATM)