Please consider first scenario ( packet switched network)
CE f0-----------fe PE--rest of network
CE is using CIR 10M CKT, PE has inbound policer for 10 M, bc 2M ( bits).
CE is shaping its traffic to CIR 10M, with matching bc 2M to ensure Policer never get hits and we can see any drops on CE that gets tail dropped.
So far so good.
Now take 2nd scenario with Cisco ONS 1544
CE f0-------f0 PE -SONET ( STS-1)
Above we have packet switched network and SONET ( TDM). CE has CIR of 50M, but PE is not enforcing any policing on f0. So CE can send more than 50M to PE, how does PE deals with traffic more than CIR? In first case, PE can determine if the traffic is exceeding by using burst size, but in 2nd case PE is not using any Policer .
This is my hunch:
1) PE can not determine the if the traffic is exceeding CIR or not when received from CE.
2) Traffic will be queued until it can be transmitted out of SONET interface, traffic will continue to be queued until red drop occurs or tail drops occurs or PE can find the time slot to transmit the queued data in SONET frame.
3) Key thing is PE has no way to determine if the traffic is exceeding, it simply queues the traffic until It can be transmitted in SONET frame or queue gets filled.
I do not know much about SONET , so excuse my ignorance.
Thanks and have a nice weekend!!
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