Content

| Overview

Traditionally, separate networks have been designed, and implemented within the enterprise for data, voice, and video applications. These have been deployed in parallel and operated in isolation, often implemented and managed by separate teams.

In the past, networking vendors typically offered similar enterprise network architectures that were, almost without exception, proprietary, closed, and non-hierarchical.

These separate networks encompass the enterprise local and wide-area networks, and have been built to interconnect private branch exchange (PBX) equipment, H.320 videoconferencing equipment and routers. The networks have been provisioned over dedicated leased lines for PBX and H.320 video, with a combination of leased lines, Frame-Relay, and ATM for data.

As client/server networking grew, the needs of enterprises were also evolving. Applying technology to business practices such as sales, support, customer response management, accounting, and supply chain was reaping tremendous benefits in increased efficiency and lower costs. Many of these new technologies supported entirely different business models (for example, business-to-consumer e-commerce, business-to-business online exchanges, etc.). In other cases they were used to re-engineer existing business practices. In all cases, the needs for reliability, performance, and ease of deployment and management remain crucial because these applications have become more critical to an enterprise's success (whether profit-making or service-oriented).

In networking today, corporations are looking for strategies to integrate disparate networking technologies over a single common network infrastructure. This trend started many years ago in the internetworking area when corporate networks began the migration of delay-sensitive, mission-critical Systems Network Architecture data traffic across an IP infrastructure. Now, people are examining the existing and often separate data, voice, and video network infrastructures and determining the most efficient ways of bringing these together.

Most corporations have voice networks anchored around private branch exchange (PBX) systems, while most data networks are IP-based and anchored around switches and routers. Where traditional telephony in fixed 64 Kbps bandwidth increments is carried across a circuit-switched PBX infrastructure, other dynamic data applications are consolidated over an intelligent IP-based backbone.