What occurs on a Frame Relay network when the CIR is exceeded?
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A. B. C. D.Explanation
In a Frame Relay network, the Committed Information Rate (CIR) is the guaranteed bandwidth that the service provider has agreed to provide to the customer. When the CIR is exceeded, the network may start dropping packets to enforce the contracted service level. The correct answer to the question is option D: All traffic exceeding the CIR is marked discard eligible.
Discard eligible (DE) is a bit in the Frame Relay header that indicates if a packet can be discarded by the network if congestion occurs. Frames with the DE bit set are low-priority traffic and are the first to be dropped in case of network congestion.
When traffic exceeds the CIR, the network marks the excess traffic as DE. This means that frames that exceed the CIR have the DE bit set and are more likely to be discarded by the network if congestion occurs. By marking traffic as DE, the network is prioritizing CIR traffic over non-CIR traffic and attempting to preserve the contracted service level.
Therefore, option D is the correct answer, as all traffic exceeding the CIR is marked discard eligible. Options A, B, and C are incorrect because they only specify TCP or UDP traffic and/or BECN messages, which are not necessarily related to CIR violations.