ion." Various vendors have developed many packaging methods for functions deemed to be of value to data-intensive metro access/metro core applications. According to market research, optical Ethernet services in the MAN are expected to take an increasing share of the lit services market, rising to 20 percent by 2005 and representing approximately $6 billion in revenues. This implies that the total metro optical market will be $30 billion in 2005. Pioneer Consulting predicts that the next-generation SONET market will grow to approximately $6 billion by 2004 (representing another 20 percent of that total; the implication would then be that the balance, or 60 percent, remains in traditional SONET equipment). The reasons for the growth in next-generation SONET are quoted as follows: Capability to interoperate with existing SONET networks New system architectures that enable simple capacity and service upgrades New enabling technologies that increase network revenue-generating capacity by as much as an order of magnitude Native data and video interfaces that reduce the number of NEs Functionality that combines digital crossconnect systems (DCS), edge routing, and add/drop multiplexing (ADM) functionality into a single NE for reduced overlay and purpose-built networks Figure 4-3 is a protocol-model view of both traditional and next- generation SONET. Figure 4-4 illustrates what a typical next-generation SONET network element might look like from a plug-in standpoint. Typi- cal functions include time slot assignment (TSA), time slot interchange (TSI), hairpinning, broadcast, and drop and continue; support of packet- mode trunking is also included in some products. In next-generation SONET, you look for cheaper transport and network elements, but with a full complement of OAM&P capabilities. Because of its emphasis on customer-ready interfaces such as Ethernet, next-generation SONET is generally more applicable to the metro access portion of the net- work than the metro core (see Figure 4-5). Examples of next-generation S