lly, networks have employed two types of devices at the edge: Access-oriented devices-These devices include MSPPs, which can handle all the popular data protocols and interfaces, except that not all of them are designed to be optical aggregators. Transport-oriented devices-These optical aggregations systems support a full range of hierarchical aggregation, from DS-3 to OC-192. They offer electrical-to-optical conversion as well. But they don't offer all the data interfaces. The Next-Generation Network Infrastructure Access Routers Switch Switch Circuit Emulation Voice Access Concentrator Frame Relay Frame Relay Switch Voice over IP VolP Gateway Figure 10.6 Complexities with single-purpose boxes Circuit Emulation Voice over Frame Relay OC-3 to OC-192 Voice over IP Switch Frame Relay Voice over ATM Figure 10.7 Simplicity with multipurpose switches Chapter 10 Next-Generation Networks Successful edge devices need to handle multiprotocol data services as well as multispeed aggregation. Emerging solutions for the intelligent network edge there- fore have to meet four critical objectives. First, there's a need to bridge the band- width bottleneck that currently exists between user LANs and the optical core. We have LANs that operate at 1Gbps (Gigabit Ethernet, or GigE) and even 10Gbps (10 Gigabit Ethernet, or 10GigE), and 100Gbps Ethernet is in development. We have optical cores that operate at 10Gbps (OC-192) and are moving beyond that, to 40Gbps (OC-768), with some hoping to introduce even 80Gbps. By applying multiple wavelengths in a fiber, we can achieve terabits per second. But the WAN link between the LAN and the optical core is still often limited to a link that can handle only 56Kbps to 2Mbps. So a severe bottleneck is occurring at the LAN/ WAN integration point, and that needs to be addressed. Second, we need to improve the serviceability of the carrier networks; we need to make it easier to define, provision, bill, and manage services and equipment across a converged area. Third, we need to enable converged ca