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The only publication dedicated to OSS Volume 2, Issue 4 - September 2005 |  |
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The combination of a UNI and NID found in Ethernet demarcation devices enable carriers to deliver Ethernet services with more service intelligence and flexibility than frame relay or private line. In particular, Ethernet provides the ability to remotely change service bandwidth without requiring a site visit to add T1s or swap a T1 for a T3. It provides the foundation for customer network management systems that will provide more service intelligence and flexibility than those found in frame relay and private line services. Intelligent Ethernet Services The Metro Ethernet Forum has defined a set of Ethernet services that is gaining widespread adoption by carriers deploying Ethernet services. They define two service types E-Line and E-LAN which represent point-to-point and multipoint-to-multipoint service types. The vast majority of Ethernet services today are E-Line services, but many carriers are also rolling out E-LAN services as well. In order for Ethernet services to replace legacy frame relay and private line data services, it is critical that Ethernet performance parameters be incorporated into service level agreements that include penalties and rebates. The following four service parameters are critical to defining a carrier grade intelligent Ethernet service. • Availability – Service uptime expressed as a percentage of time e.g., 99.99% or 99.999% availability for the service • Frame Delay – The maximum frame delay for X percent of CIR conforming frames are continuously monitored over a specified interval – can be specified on either a round trip or one-way basis. Round trip is adequate for most application, while one-way is important for broadcast applications such as video. • Frame Jitter – Defined as difference between the max and min delays in the frame delay test. • Frame Loss – The percentage of CIR conforming frames that are dropped during transport. These service parameters can be utilized to define a SLA as: • Availability – Service availability shall be measured continuously on an end-to-end basis. Service shall be available 99.99% of time in a given billing month. This equates to no more than 5 minutes downtime a month. • Frame Delay – Frame delay is measured continuously on an end to end (service) basis. The maximum (and minimum) frame delay for 99 percent of CIR conforming frames are continuously monitored over 15 minute intervals, and reported on a monthly billing cycle. Round trip delay will not exceed 50ms for more than three 15 minute intervals per billing cycle. • Frame Jitter – Frame jitter shall be measured continuously on an end-to-end (service) basis. It will be calculated over 15 minute intervals and reported on a monthly billing cycle basis. It shall not exceed 30 ms for more than three 15 minute intervals. • Frame Loss – The number of CIR conforming frames that are accepted at the service ingress UNI is continuously monitored and compared with the number of frames delivered at the service egress UNI. On a month basis, 99.95% of accepted frames will be transported without error to the far end.
© 2005, All information contained herein is the sole property of Pipeline Publishing, LLC. Pipeline Publishing LLC reserves all rights and privileges regarding the use of this information. Any unauthorized use, such as copying, modifying, or reprinting, will be prosecuted under the fullest extent under the governing law. |
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