Ethernet Services are hot. End users want to buy them. Service providers want to deliver them. Among the issues that need to be addressed for Ethernet services to be successful are:

• How can a service provider provide a clear demarcation at the customer premises, control bandwidth usage and ensure SLA conformance?

• What is the most economical way to deliver Ethernet services over a SONET transport network? Or over DSL?

• How can traditional TDM services such as T1 PBX trunks be supported over the Ethernet connection?

 

The exponential growth of corporate Internet traffic and inter-office applications such as intranets, email, enterprise VoIP and video-conferencing, are creating significant opportunities for service providers and operators of metropolitan and wide area networks who use Ethernet as their access and transport technology. On the other hand, these new Ethernet-based data networks are still not optimized for this environment: They typically lack a clear demarcation point at the customer premises, cannot monitor and enforce SLA agreements, fail to provide adequate OAM capabilities and do not match the uptime characteristics that customers demand. Furthermore, these networks do not support the cash-generating legacy services such as TDM voice trunks or other TDM or analog services.

 

For the most part, service providers are still relying on their extensive deployment of SDH/SONET rings to transport traffic in the metropolitan area network (MAN). There are significant advantages to SDH/SONET: 99.999% uptime and availability; nearly universal reach within the metro and wide area; and optimal support for voice and mission-critical legacy data applications. As a result, many service providers are leveraging their SDH/SONET infrastructure to provide transparent LAN services.

 

However, some forward-looking service providers are starting to deploy new high-speed metro Ethernet rings optimized for carrying high-speed data traffic to end customers. Connecting the end users to these metropolitan Ethernet rings is mainly done using fiber or wireless with Fast Ethernet or Gigabit Ethernet interfaces at the customer premises.

End users are interested in finding a simple, inexpensive solution to deliver Ethernet-based corporate data and LAN traffic from various local and regional offices over a high speed network. They prefer to have all their LANs operate as one, transparent to the service provider’s own facilities and without having to deal with the complexity or expense of wide area networking. Service Providers, by the same token, are challenged to create this type of “wide area LAN service” using their current E1/T1, E3/T3 or STM-1/OC- 3 fiber and coax infrastructure.

Internet service providers (ISPs) and application service providers (ASPs) must meet their corporate customers’ demands for better service and higher speed Internet access. Fierce competition in this field is forcing them to become more aggressive by introducing new data service packages and extending their coverage area. At the same time, to lower operating costs and improve profitability, ISPs and ASPs have to rely more and more on the access and backhaul facilities provided by other carriers, in many cases SDH/SONET, to transport their customers data traffic between PoPs. This situation also holds true for large corporations supplying data services to their branches.

 

Carriers operating SDH/SONET infrastructure need to support these Ethernet –based data services, including their own internal requirements for connecting POPs and data centers, without having to deploy a separate Ethernet transport network.

The most economical and least complicated solution to the problem of running Ethernet traffic over a TDM/SONET transport network is through the deployment of compact interface converters. These devices make it easy and economical to deliver Ethernet Services over legacy SDH/SONET infrastructures. RAD offers a full range of 10/100BaseT Ethernet-to- SDH/SONET converters, from E1/T1 to E3/T3 and STM-1/OC-3. Using single or bonded copper connections, these products support granular Ethernet bandwidth delivery, offering simple, cost-effective connection between LANs and the access network. They can also deliver Ethernet over one or multiple G.SHDSL connections.

RAD’s Ethernet Network Termination Units (E-NTUs) enable service providers to implement an Ethernet-based access local loop. These dedicated, managed devices serve as a demarcation between the customer premises and the carrier’s network. They incorporate traffic management functionality such as rate limiting and perform class of service differentiation through VLAN tagging/stacking. VLAN support allows the operator to separate each user’s traffic and offer services such as inter-office LAN connectivity, Internet access and secure virtual private networks (VPNs). This approach extends the service provider’s reach over fiber, facilitating management of differentiated services up to the customer premises.

 

The introduction of E-NTUs also makes it technically possible and economically feasible to create an Ethernet-based access network over existing SDH/SONET or ATM backbone networks. Emerging next-generation SDH/SONET standards, such as GFP, VCAT and LCAS, as well as existing ATM mapping mechanisms, enable these legacy platforms to efficiently handle Ethernet traffic handed off from the E-NTU located at the customer premises. There are several advantages to creating this kind of Ethernet access network. The incumbent service provider can begin to offer Ethernet-based access services even before finalizing its Ethernet transport strategy. Not only does this generate a new revenue stream, it also enables the operator to gain immediate experience on Ethernet as a carrier class service before making major investments in Ethernet backbone equipment.

 

TDM over Ethernet: Once a high-speed Ethernet connection is available, customers will want to converge their traditional voice services--such as T1 PBX trunks--onto their new high-speed access connection. RAD's family of TDM over Ethernet gateways use pseudowire / TDMoIP circuit emulation technology to do just this.