The dramatic growth in the demand for Ethernet services in recent years shows no sign of abating, with spending on metro Ethernet equipment predicted to rise by 134% to reach $5.9 bn (€5.2 bn) by 2006, according to data from telecoms consultancy Infonetics Research. Driving that growth is operators' pressing need for a new approach to data-service provisioning and connectivity that will enable them to respond to customers more rapidly and stay competitive in today's turbulent market.
Although voice services still constitute the bulk of telecoms revenues, data services are the focus of virtually every forecast in the industry because they look certain to fuel any future market expansion. The problem is that data services have traditionally been delivered over an infrastructure designed for voice rather than data traffic.
Early data applications were supported by analogue modems delivering at best a rather mediocre service. Telecoms operators later introduced E1/T1 services, but their features still conform to the basic building blocks of voice systems rather than the requirements of data traffic. Data-friendly protocols such as X.25 and Frame Relay were also established, with Asynchronous Transfer Mode (ATM) following, but even they fail to fulfil some of the basic needs of data applications.
Focused on data
To date, by far the most common data service for connecting different corporate sites is wide-area networking (WAN). Enterprise customers are looking for fast, efficient, cost-effective, full-mesh connectivity between sites, along with bandwidth on demand and a reliable, secure, uninterrupted service.
Another key application that puts similar demands on the transport infrastructure is Internet connectivity, which in today's data-intensive world is an essential requirement for even single-location businesses. In the past, however, this application has suffered because service providers have treated it as a special case of data-service provisioning, relying on circuit-orientated technology such as leased lines, Frame Relay and ATM, rather than designing an infrastructure to meet the specific needs of Internet Protocol traffic.
Indeed, the provision of WAN and Internet connectivity services has been based more on the carrier's installed infrastructure than on the needs of end-users. But the world of service providers is changing, and they are now looking to introduce a new wave of customer-focused technologies. Top of the list are Ethernet services, which promise a simpler and more cost-effective solution to meet the needs of data applications.
In a traditional WAN scenario, two Ethernet local-area networks are linked together with routers that are interconnected via Frame Relay or leased lines. Packets travelling from one site to the other are transferred from an Ethernet switch to local routers, which send them on to the channel service unit/data service unit (CSU/DSU) for translation into WAN technology (E1, ATM or Frame Relay). The packets are then delivered to the remote CSU/DSU and router, which sends them to their final destination via the remote Ethernet switch.
In contrast, Ethernet services can be delivered via a fibre carrying Ethernet traffic between the remote and local Ethernet switches, as if they were joined by a physical wire. This eliminates the need for CSU/DSUs, because local and remote Ethernet switches are connected directly to a fibre provided by the service provider, which may optionally install some simple equipment at the customer premises for monitoring line connectivity and quality. And routers are no longer needed because the two Ethernet switches are connected directly, while Ethernet's learning mechanism ensures that each packet is sent to its correct destination.
What's more, Ethernet's simplicity and autoconfiguration features apply to both LAN and WAN services. No configuration of routing tables is required, while simple automatic learning mechanisms provide an effortless, transparent LAN service.