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Carrier Ethernet
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Traditional Ethernet, as used in the LANs, has always been a best-effort, broadcast technology. These properties of Ethernet were inherited due the birth of Ethernet in the LANs. Enterprise LANs are usually high-speed, and hence there is seldom a need for congestion control. Security is not a concern in these LANs as they are within an enterprise,. Also, since the enterprise LAN was spread over a geographically small area, the OAM capabilities of Ethernet were never well developed. As almost all traffic within a LAN was data traffic, it did not require extensive protection schemes and redundancy.
However, as Ethernet makes its way into the Carrier networks, work has begun on providing carrier class Ethernet services. Tejas Networks has extensive experience in designing carrier-class equipment for SDH networks, and is actively working towards bringing its expertise into carrier-class Ethernet networks. In order to co-ordinate with carrier-Ethernet efforts worldwide, Tejas Networks is also a member of the MEF.
ATTRIBUTES OF CARRIER ETHERNET
So, what is ‘Carrier Class Ethernet’? Carrier Class Ethernet is a service that is characterized by the following 5 attributes:
- Standardized Services
The MEF has put significant effort into the standardization of Ethernet services over the last few years. While Ethernet services existed before these efforts, the MEF plays a key role in the industry by providing a common set of tools and terminology that will define consistent characteristics of these Ethernet services that service providers, system vendors, and enterprises will all be able to refer to regardless of the specific type of network infrastructure whether it is Sonet/SDH, dark fiber, MPLS, ATM, or RPR.
- Scalability
This attribute deals with the scalability of Carrier Ethernet in terms of Services, Subscribers and Bandwidth. The scalability with respect to services implies that the network should be able to provide a wide range of Ethernet services to as many customers as possible. The very fact that an Ethernet interface is being presented to the customer gives the advantage of bandwidth scalability. The customer can upgrade in simple increments without change of equipment. And for larger increments the customer can just use up an additional port on the Customer Premises Equipment.
- Reliability
Reliability is the attribute that ensures that the network can detect and recover from incidents without affecting user service. In that regard, SDH/SONET has set the gold standard of 50ms protection (the traffic is restored within 50ms of an incident), and the network should meet this standard. A ‘Carrier Ethernet’ network should meet the most demanding quality and availability requirements.
- Quality of Service
The Carrier Ethernet network should guarantee end-to-end performance. Standardization enables convergence of services onto a Metro Ethernet network, and this implies that the network should match the requirements of a variety of traffic. While Voice services and Streaming media require stringent QoS, Internet connectivity requires best effort. However, the Carrier Ethernet network should guarantee end-to-end performance to defined Service Level Agreements (SLAs) based on Committed Information Rate (CIR), Excess Information Rate (EIR), frame loss, delay and delay variation characteristics.
- Service Management
This attribute deals with how quickly a service can be provisioned and how it can be monitored and diagnosed. Legacy services required a network operator to provisions each node, if a new service was required. However, in a Carrier Ethernet network, the Network Operator should be able to provision services quickly from the Networks Operations Center (NOC). The Carrier Ethernet Network should possess carrier-class OAM (Operations, Administration and Maintenance) capabilities. It should be possible to monitor, diagnose and centrally manage the network. This means, in case of errors, not only will the Network Operator be able to isolate the fault quickly, but will also be able to take corrective action from the Network Operations Center.
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