NOTE From a Service Provider??™s standpoint, the CESoE is actually just an Ethernet
service.
The MEF 3 has also defined performance expectations for the Service Provider network
delivering the CESoE to ensure that toll-grade voice quality is maintained. Specifically,
it identifies the following four Class of Service (CoS) characteristics: Ethernet frame
delay, Ethernet frame delay variation (jitter), Ethernet frame loss, and network availability.
These parameters should conform to values consistent with those in a typical
TDM environment (i.e., five 9s network availability, less than 10 ms jitter, and so on).
Implementation Support MEF 8 provides further detail on implementing the requirements
specified in MEF 3 when supporting PDH services over a MEN/Service Provider
Ethernet Network (SEN). In so doing, the specification is attempting to address the
inherent challenges of transporting TDM signals. The technical challenges faced by
CESoE primarily stem from replicating constant bit rate TDM services over a variable
bit rate Ethernet infrastructure. These challenges include packetization, frame delay
variation, clock recovery, and synchronization and TDM performance monitoring.
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