Telecoms Infrastructure Technology - Volume 2 - Long Distance & Data

We begin with a detailed description of long distance optical fibre technologies, including submarine cables with optical amplification supporting dozens or hundreds of wavelengths with Wavelength Division Multiplexing (WDM). A number of subtle physical processes, including chromatic and polarization mode dispersion, four-wave mixing and self-phase modulation set the upper limits for the data carrying capacity of any fibre system. We discuss these and the techniques of Erbium Doped Fibre Amplification and Raman Amplification, to provide detailed insight into the current state of the art for long distance fibre communications. Satellite and microwave long distance links are also discussed.

We then consider traditional and advanced methods of modulating data, including G.709 Optical Transport Network, which uses Forward Error Correction to reliably carry SDH/SONET and packetised data over fibre links in conditions of low signal-to-noise ratio. This important development greatly enhances capacity and robustness of WDM systems. We discuss the established, highly reliable, SDH/SONET ring architecture which is the basis of most carrier backbone networks today, and the use of new technologies, including Resilient Packet Rings, optical switching and Generalised Multiprotocol Label Switching (GMPLS) to build flexible, redundant, long distance networks.

We discuss the various Ethernet physical technologies, including 10 and 40 Gigabit per second fibre, and the way Ethernet framing and transport of data is increasingly preferred over SDH/SONET and the older techniques of Frame Relay and ATM (Asynchronous Transport Mode).

This report provides an extensive introduction to Quality of Service (QoS) and Multiprotocol Label Switching (MPLS) techniques, which are essential for the reliable delivery of voice, data and video services using Ethernet and TCP/IP packet technologies. Carriers face many challenges integrating their currently disparate networks, traffic types and services into a common packet-based core network. The report provides vital insight into the challenges of providing full end-to-end QoS reservation of bandwidth and assurance of packet delivery over both core and edge (last-mile) networks.

We also discuss conventional ISDN SS7-based telephone networks, PABXs (Private Automatic Branch Exchanges) and PC software implementations of PABX functionality, including the open-source Asterisk project.

While this report does not assume an engineer’s depth of prior technical knowledge, it provides a solid overview of telecommunications core networks, data carriage and switching techniques to enable the non-specialist to understand the technology in ways he or she can apply to their own situation.

The companion volume to this report is available and provides an independent introduction to Last Mile broadband technologies: 2006 Telecoms Infrastructure Technologies Handbook - Volume 1 - Last Mile.