ollowing are disadvantages of ATM: Has small cell size Has high overhead Has high service costs Requires new equipment Requires new technical expertise Another disadvantage of ATM is that confusion arises when some of the capabili- ties of ATM begin to be offered by other approaches, such as Multiprotocol Label Switching (MPLS), as discussed in Chapter 10. Chapter 7 Wide Area Networking Current ATM Status With the growing popularity of networks based on IP, ATM has a declining future. Nonetheless, the majority of telcos have implemented ATM in their WANs over the years, and most ADSL implementations use ATM. ATM is therefore not going away anytime soon. After all, significant investments were made, and still today, ATM offers the best way to ensure QoS and traffic management. The problem is that most vendors have dropped out of the ATM marketplace in favor of MPLS and other native IP solutions. ATM will continue to be used where it is deployed, in higher- speed interconnects, unifying PDH/SDH traffic and packet-switched traffic under a single infrastructure; in multiplexing services in support of DSL networks; and in carrying the majority of IP traffic. Interestingly, MPLS, the latest IP enhancement, borrows many of its technically sound ideas from ATM, enabling similar QoS capa- bilities without the cost and complexity of ATM. (MPLS is discussed in Chapter 10.) Where ATM failed to gain widespread use was in the LAN environment, largely due to the emergence of Gigabit Ethernet, which provides high speeds at a much lower cost than ATM and without the complexity associated with ATM. Therefore, ATM did not realize its intended goal of being the single integrating network tech- nology. As a result, most telcos are now planning to integrate voice and video traf- fic onto their IP networks, using MPLS to address the growing need for QoS to manage real-time traffic flows such as voice, video, and multimedia. Based on cur- rent trends, it is also likely that 10 Gigabit Ethernet will begin to replace ATM in many locations