Definitive MPLS Network Designs [Electronic resources] نسخه متنی

Chapter 4. National Telco Design Study

Telecom Kingland (TK) is a fictitious Internet service provider (ISP) based in the imaginary country of Kingland. It is representative of an incumbent telecommunications service provider in Europe or Asia. Such providers are often called telcos. These providers used to provide services to the national regulated markets and were owned by their respective governments, operating predominantly as a monopoly. In the face of deregulation of the national markets, and the opening of those markets to competition, telcos have been undergoing drastic changes. These changes include partial or complete privatization, rationalization of assets and operational expenses (opex), and internal reorganizations that help the telcos offer competitive services and prices in this new landscape.

Because of their common history, many telcos exhibit similar characteristics. They typically have a very broad service portfolio covering all telecommunications services, including fixed telephony, mobile telephony, and data. They generally have complete nationwide geographic coverage with a very dense service footprint, and they own fibers and transmission facilities. Despite increasing competition, they typically have retained a significant market share in their domestic markets.

To support all the new services that have emerged over the years, many telcos have deployed a plethora of overlay and parallel networks. Today, they are seeking significant cost reductions through the migration of many services onto a next-generation multiservice packet-based backbone network. TK identified such a migration as a key strategic direction. To that end, TK evolved its packet core as a nationwide multiservice network over which multiple existing services (such as IPv4 Internet and Layer 3 MPLS VPN services) have been migrated. This network is also used for Public Switched Telephone Network (PSTN) trunking and the introduction of new services (such as IPv6 Internet).

The vision underpinning this network integration is a very strong separation between the core network, which is designed as a high-performance, high-quality, service-independent infrastructure, and the edge network, which is designed to be multiservice-capable and feature-rich.

The objective of this chapter is to discuss the specifics of the IP/MPLS network design chosen by a particular network operator, illustrative of a national telco. This chapter shows how the characteristics and objectives of this type of operator influenced the design decisions that were made and also discusses the design evolutions.