Traditional IP packet forwarding analyzes the ( 1)IP address contained in then network layee header of each packet as the packet rravels from its sourse to its final destination. A router analyzes the destination IP address independently at each hop in the network. Dynamic ( 2) protocols or staitic configuration builds the database needed to analyze the destination IP address(the routing table). The process of implementing traditional IP routing also is called hop-by-hop destination-based ( 3)routing. Although successful,and obviously widely deployed,certain restrictions,which have been realized for some time,exist for this method of packet forwarding that diminish its ( 4).New techniques are therefore required to address and expand the functionality of an IP-based network infrastructure. This first chapter concertrates on idenfifying these restrictions.and presents a new architecture,known as multiprotocol( 5)switching,that provides solutions to some of this restrictions.