Ethernet everywhere: Delivering services in a private line world

For data communications requirements in the Metropolitan Area Network (MAN) or Wide Area Network (WAN), Ethernet services represent an ideal solution for enterprises and a means for service providers to offer differentiation in their service offerings and product bundles. With over 99 percent of new port sales in the Local Area Network (LAN), Ethernet is the de facto standard. Given this ubiquity, end-users have substantial experience in the design and implementation of Ethernet networks, while comparatively few individuals are acquainted with the nuances of the modern telecommunications infrastructure. As such, there is tremendous familiarity and comfort on the part of end-users with Ethernet. End-users would prefer to use Ethernet for connectivity between LAN environments across the MAN and WAN as well as for an access technology to the Internet and other shared network infrastructures.

Traditionally, unique networks evolved to serve specific needs. Within the WAN, time division multiplexing (TDM) based networks evolved to support the public voice network. Within the LAN, numerous protocols and technologies evolved to support data transport. Over time, Ethernet became the predominant means of delivering data in the LAN, and Synchronous Optical NETwork (Sonet) networks became the predominant means of delivering TDM services. However, as data networking requirements evolved and enterprises and other customer segments developed needs to deliver data across the MAN and the WAN, customers were given no choice but to utilize the private line connections developed for the voice network as the transport mechanism for their Ethernet LAN traffic.

The challenges are apparent to anyone who has dealt with data communications beyond the LAN: The 10 Mbit/sec, 100 Mbit/sec, and 1000 Mbit/sec speeds present in the LAN do not map well to private line services (45 Mbit/sec, 155 Mbit/sec, 622 Mbit/sec, and 2.4 Gbit/sec) resulting in wasted WAN capacity or throttling of the LAN connections. The costs of private line interfaces like DS3 and OC-x connections are significant in comparison with Ethernet interfaces — often an order of magnitude cost differentiation.

Point-to-point Ethernet systems are established over a copper or fiber medium and provide a single connection between two user end-points. Carriers deploying GigE connections will often make use of available fiber plant to establish basic point-to-point connections for customers. Using the embedded base of Sonet systems, carriers will deploy Ethernet interfaces on the existing Sonet ADMs (Add-Drop Multiplexers). This service presents an Ethernet interface to the end-user while offering Sonet reliability. The challenge is that until the next generation of Sonet systems are available, these networks generally make inefficient use of backbone capacity.

Utilizing embedded ATM and Frame Relay systems or making use of newly deployed multi-protocol label switching (MPLS) networks, carriers can provide an Ethernet interface to end-users and deliver the desired bandwidth across the network core. In the case of ATM and frame relay networks, this allows carriers to leverage an existing asset to provide the Ethernet service customers desire.

Some carriers have built custom networks based on Ethernet technologies designed exclusively for the deployment of Ethernet services. While these networks require significant engineering to ensure that the service is delivered with the highest availability and service quality, the networks also guarantee that the Ethernet services deployed on them provide the greatest overall benefits to the end-user.

In many real world situations, these different alternatives may be combined to create an end-to-end solution for a customer. As an example, an end-user may wish to create and Ethernet-based network that links LAN environments in three metropolitan areas throughout the U.S.

In order to facilitate this network, the end-user may make use of an Interexchange carrier's (IXC) MPLS-based backbone network with Ethernet interfaces in each of the three metros. From the IXC's points of presence in each metro, the end-user will need metro Ethernet providers to extend Ethernet connectivity to the end-user locations in each metro. Depending on the facilities and providers that are present in each metro, the end-user may make use of multiple providers to provide that last mile Ethernet connection.

Expanded benefits

Ethernet services offer tremendous benefits to both end-users and the service providers delivering the service. In the case of end-users, the benefits can be separated into three main categories: Lowered total cost of ownership (TCO), increased flexibility, and ease of use. The lowered TCO comes from a reduced initial cost to deploy the service based on the dramatic difference between Ethernet interfaces and typical private line interfaces, as well as a service price that is typically lower on a cost per Mbit/sec basis than a comparable private line service.

The increased flexibility means end-customers are not constrained to traditional private line speeds, but are able to choose between connection speeds that are much more granular. Additionally, some Ethernet providers are supporting scalability of bandwidth - meaning end-users can adjust the bandwidth of their connection as their needs require without re-provisioning a circuit, as would be required with a private line connection. And, the fact that Ethernet technology is more broadly understood means that end-users are able to monitor and manage their networks more effectively while reducing the necessity for costly telecom experts on the payroll.

For the carriers deploying Ethernet services, there are additional benefits that are present. The first is the ability to offer a differentiated service offering. With high demand for the service and many providers slow to deploy a robust Ethernet offering, carriers who can serve their end-user Ethernet requirements will be able to quickly differentiate themselves in the market. Tying into this differentiation is an increased ability to bundle service offerings. And, there is little doubt of the benefit to end-users of obtaining Ethernet-based access to carrier's ATM and frame relay networks. Also, customers are demanding Ethernet based private networks that span the MAN and WAN.

Those carriers responding to these demands will be able to provide a higher revenue bundle and improve ability to own the end-user's full service experience. Finally, while the engineering and architecting of a carrier class Ethernet network adds costs to the network deployment such that it approaches that of a typical private line network, the carrier still may benefit from lower cost Ethernet interfaces at the edge of the network. Just as for the enterprise customer, the cost of Ethernet ports are substantially less than comparable speed Sonet OC-x interfaces on carrier equipment.

Ethernet-based services offer tremendous benefits to end-users. With a lower TCO, increased flexibility in deployment and common framework for understanding, Ethernet services are the logical solution for most end-user data communications needs in the MAN and WAN. Given this, carriers who take the initiative and enable carrier class Ethernet services that support the granularity and scalability requirements of end-users will rapidly differentiate themselves from others in the market and deliver unique product bundles to end-users.