Etherjack: Ethernet in the Metro access and beyond--Part II

Etherjack technology offers key functional capabilities:

• Physical demarcation--The Etherjack device marks the physical distinction between the enterprise and service-provider domains (Figure 1), which is important for addressing the carrier challenge of expediting trouble shooting. Etherjack extends the physical demarcation point into a customer premise, and the carrier gains visibility of the Ethernet services even when relying on leased last-mile infrastructure. In addition, the Etherjack also establishes the User Network Interface (UNI), which ensures a consistent look and feel to the enterprise end user. Further, the UNI provides traffic-management capabilities, enabling support of very different services, each treated with a relative priority. The UNI, therefore, provides a common entry point for all converged services at the service provider, thereby simplifying and standardizing the delivery of Ethernet services.
• Media conversion--The Etherjack device allows an Ethernet handoff over disparate last-mile access technologies, which is important for addressing the carrier challenge of serving enterprise-customer sites that are not directly connected by fiber. The Etherjack typically supports different WAN transport technologies (from T-1 and DS-3 to OC-n). From an end user standpoint, the handoff is standard Ethernet (say an RJ-45 handoff), and the access technology is not visible and, in fact, irrelevant to the end user. With this media-conversion capability, Etherjack enables Ethernet to be offered over a variety of last mile technologies.
• End-to-end OAM--The Etherjack device also provides end-to-end OAM capabilities, which are important for overcoming the carrier challenge of quickly and cost-effectively isolating and eliminating issues. The Etherjack leverages underlying operations- and performance-management capabilities such as loopback, continuity checks, trace route and other fault-management functions to proactively manage any emerging issues and, therefore, ensure a better end-user experience. By effectively automating the fault-management capability, expensive truck rolls are eliminated, significantly cutting carrier OPEX.
• SLA measurement--Etherjack provides a very effective mechanism to measure the SLA associated with the Ethernet services. Typical components of such an SLA (packets dropped, availability at a particular QoS, jitter, delay, etc.) can be easily measured over user-defined intervals, and any variance can trigger an alarm. Such a capability is vital to end users as they begin to migrate mission-critical applications to Ethernet from traditional offerings such as Frame Relay and ATM.

Etherjack's capabilities go a long way to address the main issues with the delivery of Carrier Ethernet services today. Notably, by providing the ability to offer consistent Ethernet services across different infrastructure, it extends the feasibility of Ethernet services across the entire access network.

Enabling ubiquitous Carrier Ethernet
Employing Etherjack demarcation enables carriers to offer Ethernet services ubiquitously, independent of the different last-mile technology infrastructures (as depicted in the real-life scenario illustrated in Figure 2). Consider the example of a business such as a bank with multiple locations, each served by different last-mile transport such as T-1, T-3 and OC-n, over fiber and copper infrastructure and possibly across multiple carriers' footprints. Typically, offering an Ethernet service to such (an economically attractive) customer, let alone a consistent offering, is a challenge. Ethernet services may not be available on several of the last-mile loops serving the different bank locations. Further, many of these loops may belong to a different carrier and may have to be leased. Under such a scenario how does a carrier deliver differentiated Ethernet services competitively?

The introduction of Ethernet-demarcation devices at the end of the loop, as shown in the figure, would render the idiosyncrasies of the last-mile technologies irrelevant and enable a consistent interface across all end-user locations, regardless of the specific technologies in use.

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