A few years ago, it wasn't cool to say Sonet was sexy. Sonet was considered incredibly inefficient and inflexible – a stodgy, old-fashioned circuit technology that wouldn't survive in tomorrow's packet-based networks.
Now, everything's changed. The need for carriers to make a better return on investment has forced them to recognize that nearly all of their revenues come from services provided over circuits. At the same time, Sonet has undergone some radical improvements – notably ones that slash costs and eliminate many of its ineffiencies in handling packet-based traffic.
These developments have particular relevance to metro networks, where most of the action is right now, for a couple of reasons. First, this is where the rubber hits the road in terms of marshalling packet-based traffic and feeding it into the big fat optical pipes in carrier backbones. Second, cost considerations are very important in metro networks.
This report digs into these developments. It's part of a series of articles that freelance analyst Tim Hills has researched and written for Light Reading. The series is intended to put metro technologies into context, make them more understandable, and help folk see through the marketing hype pumped out by component and equipment suppliers.
The first report, Metro Multiservices Evolution, set the scene by explaining why metro networks are hot, the challenges facing carriers, and the technologies being proposed to solve these problems.
This report focuses on what's become known as Next-Generation Sonet. Its emphasis is on systems, while another report, covering Sonet chip developments, is scheduled for publication here in early June. (It will be previewed in a free, live Webinar on May 28. Click here to register.)
Subsequent reports in this series will delve into the details of "carrier-class" Ethernet, Resilient Packet Ring (RPR), and dense wavelength-division multiplexing (DWDM) developments.
This report starts by examining what the term Next-Generation Sonet really means and then reviews the technologies covered by the brand name. It then goes on to identify key trends in chip developments and outlines the ways next-gen Sonet is being built into metro equipment. Finally, it surveys a selection of products from key vendors in this space.
Here's a hyperlinked summary:
The Next-Gen Brand
- Old Sonet's limitations
- What New Sonet brings to the table
- The (big) influence of Ethernet
- Packet-over-Sonet developments
- Where digital wrappers fit in
- Generic framing procedure versus X.86
- Virtual concatenation pros and cons
- Faster, faster
- Smaller, smaller
- Transceiver transformations
- How next-gen Sonet is being used in equipment
- Delivering flexible bandwidths
- Grooming multiprotocol traffic streams
- Selected equipment developments from key vendors
- Monster build-your-own table
- Heavy-duty dope on equipment specs
Here's some background reading that might also help:
- Beginner's Guide: Protocol Basics
- Beginner's Guide: Sonet (Synchronous Optical NETwork) and SDH (Synchronous Digital Hierarchy)
- Beginner's Guide: Digital Wrappers and Forward Error Correction (FEC)
- Beginner's Guide: Ethernet
- Report: Tutorial on Grooming Switches
- Report: Metro Multiservices Evolution
About the author: Tim Hills is a freelance technical writer. He may be reached at: email@example.com.
Next Page: The Next-Gen Brand