Frame Relay -VC Rate Control
Committed Information Rate (CIR)
- defined, “guaranteed” for each VC
- negotiated at VC set up time
- customer pays based on CIR
DE bit: Discard Eligibility bit
- Edge FR switch measures traffic rate for each VC; marks DE bit
- DE = 0: high priority, rate compliant frame; deliver at “all costs”
- DE = 1: low priority, eligible for discard when congestion