The actions for UPC and NPC in the ATM protocol are defined in ITU-T Recommendation I.371 Traffic control and congestion control in B ISDN [2] and the ATM Forum's User-Network Interface (UNI) Specification.
However, this single implementation must be able to access the parameters relating to a specific connection using the VCI and or VPI to address them.
This is often done using Content-addressable memory (CAM), where the VCI and or VPI form the addressable content.
Cells that fail to conform, i.e. because they come too soon after the preceding cell on the channel or path because the average rate is too high or because the jitter exceeds the tolerance, may be dropped, i.e. discarded, or reduced in priority so that they may be discarded downstream if there is congestion.
Transmissions onto an Avionics Full-Duplex Switched Ethernet (AFDX) network are required to be limited to a Bandwidth Allocation Gap (BAG).