Editing Traffic policing (communications) (section)

=== Impact in the case of ATM ===
Where [[cell relay|cell]]-level dropping is enforced (as opposed to that achieved through packet-based policing) the impact is particularly severe on longer packets. Since cells are typically much shorter than the maximum packet size, conventional policers discard cells which do not respect packet boundaries, and hence the total amount of traffic dropped will typically be distributed throughout a number of packets. Almost all known [[ATM Adaptation Layer 5#Convergence, segmentation, and reassembly|packet reassembly]] mechanisms will respond to a missing cell by dropping the packet entirely, and consequently a very large number of packet losses can result from moderately exceeding the policed contract.