If the source does not limit its sending rate (for example, through a feedback mechanism), this will continue, and may appear to the recipient as if link errors or some other disruption is causing random packet loss.
With reliable protocols, such as TCP as opposed to UDP, the dropped packets will not be acknowledged by the receiver, and therefore will be resent by the emitter, thus generating more traffic.
[citation needed] Co-operative policing mechanisms, such as packet-based discard[1] facilitate more rapid convergence, higher stability and more efficient resource sharing.
Where cell-level dropping is enforced (as opposed to that achieved through packet-based policing) the impact is particularly severe on longer packets.
Marking can comprise setting a congestion flag (such as ECN flag of TCP or CLP bit of ATM) or setting a traffic aggregate indication (such as Differentiated Services Code Point of IP).
In simple implementations, traffic is classified into two categories, or "colors" : compliant (green) and in excess (red).
[5] On Cisco equipment, both traffic policing and shaping are implemented through the token bucket algorithm.
Connection-oriented networks (for example ATM systems) can perform Connection Admission Control (CAC) based on traffic contracts.