Many service providers implement MANs by using Synchronous Optical Network (SONET) or Ethernet. SONET is a physical layer standard, and is described later in this chapter. It provides more bandwidth than Ethernet, and supports multiple Layer 2 technologies, such as ATM, IP, and even Ethernet. Ethernet, as a standalone solution, is used typically for the following reasons:
Scales to very high speeds (10Gbps)
Is a widely used and proven technology
Supports multiple services, including voice, video, and data
Cisco sells many metro solutions. Actually, many of the products that you would find at the distribution and core layers of an enterprise network are considered candidates for metro products ...