Method, apparatus and system for granular policing based on multiple arrival curves
A method for granular policing includes a novel policing architecture which evaluates an arriving cell's conformance by comparing the actual arrival characteristic against a family or a set of expected arrival curves. In embodiments of the present invention, expected arrival characteristics based on a connection service level agreement (SLA) are represented by a family of N arrival curves. The degree of non-conformance of a cell is evaluated by inspecting, which m arrival curves were violated and which N-m arrival curves were non-violated by the arriving cells. Subsequently in context of discard, non-conforming tagged cells are further prioritized based on their degree of non-conformance. Thus cells associated with a higher degree of non-conformance shall be discarded before cells with a relatively lower degree of non-conformance.
1. A method for enforcing a transmission control parameter for a virtual connection including multiple cells within an input port, the virtual connection having a nominal inter-cell arrival rate increment, wherein the multiple cells are associated with a theoretical arrival time and an early arrival limit, said method comprising:
delineating a lower boundary of a conformance zone for said transmission control parameter by determining a difference between the early arrival limit and the theoretical arrival time;
defining a plurality of early arrival curves for said transmission control parameter, each of said early arrival curves below said lower boundary of said conformance zone;
determining an actual arrival time for an incoming cell from said multiple cells;
comparing said actual arrival time to said theoretical arrival time to determine whether said actual arrival time is later or earlier than said theoretical arrival time;
in response to determining that said actual arrival time is later than said theoretical arrival time, identifying said incoming cell as conforming to said transmission control parameter;
in response to determining that said actual arrival time is earlier than said theoretical arrival time, comparing said actual arrival time to said lower boundary to determine whether or not said actual arrival time is later than said lower boundary of said conformance zone;
in response to determining that said actual arrival time is later than said lower boundary of said conformance zone, identifying said incoming cell as conforming to said transmission control parameter; and
in response to determining that said actual arrival, time is earlier than said lower boundary of said conformance zone, identifying said incoming cell as non-conforming to said transmission control parameter and prioritizing said non-conforming cell using said early arrival curves defined for said transmission control parameter.
2. The method of claim 1 , further comprising:
in response to identifying an incoming cell as conforming to said transmission control parameter, resetting said theoretical arrival time to said actual arrival time.
3. The method of claim 1 , wherein the theoretical arrival time of a next arriving cell is determined by adding said nominal inter-cell arrival rate increment to said determined actual arrival time of a directly preceding cell.
4. The method of claim 1 , wherein it is determined if a cell is non-conforming with respect to said lower boundary of said conformance zone by adding the early arrival limit to said actual arrival time of said cell and comparing if the sum of the early arrival limit and the actual arrival time of said cell is greater than or less than said theoretical arrival time for said cell.
5. The method of claim 4 , wherein said cell is identified as a non-conforming cell with respect to said lower boundary of said conformance zone if the sum of the early arrival limit and the actual arrival time of said cell is less than the theoretical arrival time for said cell.
6. The method of claim 4 , wherein said cell is identified as a conforming cell with respect to said lower boundary of said conformance zone if the sum of the early arrival limit and the actual arrival time of said cell is greater than the theoretical arrival time for said cell.
7. The method of claim 1 , wherein said method comprises a virtual scheduling algorithm.
8. The method of claim 1 , wherein said method comprises a continuous-state Leaky Bucket algorithm.
9. The method of claim 1 , wherein said method comprises a token-bucket algorithm.
10. An apparatus comprising a memory and a processor for enforcing a transmission control parameter for a virtual connection including multiple cells within an input port, the virtual connection having a nominal inter-cell arrival rate increment, wherein the multiple cells are associated with a theoretical arrival time and an early arrival limit, said apparatus adapted to perform the steps of:
delineating a lower boundary of a conformance zone for said transmission control parameter by determining a difference between the early arrival limit and the theoretical arrival time;
defining a plurality of early arrival curves for said transmission control parameter, each of said early arrival curves below said lower boundary of said conformance zone;
determining an actual arrival time for an incoming cell from said multiple cells;
comparing said actual arrival time to said theoretical arrival time to determine whether said actual arrival time is later or earlier than said theoretical arrival time;
in response to determining that said actual arrival time is later than said theoretical arrival time, identifying said incoming cell as conforming to said transmission control parameter;
in response to determining that said actual arrival time is earlier than said theoretical arrival time, comparing said actual arrival time to said lower boundary to determine whether or not said actual arrival time is later than said lower boundary of said conformance zone;
in response to determining that said actual arrival time is later than said lower boundary of said conformance zone, identifying said incoming cell as conforming to said transmission control parameter; and
in response to determining that said actual arrival time is earlier than said lower boundary of said conformance zone, identifying said incoming cell as non-conforming to said transmission control parameter and prioritizing said non-conforming cell using said early arrival curves defined for said transmission control parameter.
11. A system for enforcing a transmission control parameter for virtual connections including multiple cells within respective input ports of a plurality of network nodes, the virtual connections having a nominal inter-cell arrival rate increment, wherein the multiple cells are associated with a respective theoretical arrival time and an early arrival limit for each of said network nodes, said system comprising:
at least one processing unit including a processor and a memory, adapted to respectively perform the steps of:
delineating a lower boundary of a conformance zone for said transmission control parameter by determining a difference between the early arrival limit and the theoretical arrival time;
defining a plurality of early arrival curves for said transmission control parameter, each of said early arrival curves below said lower boundary of said conformance zone;
determining an actual arrival time for an incoming cell from said multiple cells;
comparing said actual arrival time to said theoretical arrival time to determine whether said actual arrival time is later or earlier than said theoretical arrival time;
in response to determining that said actual arrival time is later than said theoretical arrival time, identifying said incoming cell as conforming to said transmission control parameter;
in response to determining that said actual arrival time is earlier than said theoretical arrival time, comparing said actual arrival time to said lower boundary to determine whether or not said actual arrival time is later than said lower boundary of said conformance zone;
in response to determining that said actual arrival time is later than said lower boundary of said conformance zone, identifying said incoming cell as conforming to said transmission control parameter; and
in response to determining that said actual arrival time is earlier than said lower boundary of said conformance zone, identifying said incoming cell as non-conforming to said transmission control parameter and prioritizing said non-conforming cell using said pluralities of early arrival curves defined for said transmission control parameter.
12. The system of claim 11 , wherein each of said network nodes comprises a respective processing unit.
13. A computer readable medium storing a software program, that, when executed by a computer, causes the computer to perform a method for enforcing a transmission control parameter for a virtual connection comprising multiple cells within an input port, said virtual connection having a nominal inter-cell arrival rate increment, wherein said multiple cells are associated with a theoretical arrival time and an early arrival limit, said method comprising:
delineating a lower boundary of a conformance zone for said transmission control parameter by determining a difference between the early arrival limit and the theoretical arrival time;
defining a plurality of early arrival curves for said transmission control parameter, each of said early arrival curves below said lower boundary of said conformance zone;
determining an actual arrival time for an incoming cell from said multiple cells;
comparing said actual arrival time to said theoretical arrival time to determine whether said actual arrival time is later or earlier than said theoretical arrival time;
in response to determining that said actual arrival time is later than said theoretical arrival time, identifying said incoming cell as conforming to said transmission control parameter;
in response to determining that said actual arrival time is earlier than said theoretical arrival time, comparing said actual arrival time to said lower boundary to determine whether or not said actual arrival time is later than said lower boundary of said conformance zone;
in response to determining that said actual arrival time is later than said lower boundary of said conformance zone, identifying said incoming cell as conforming to said transmission control parameter; and
in response to determining that said actual arrival time is earlier than said lower boundary of said conformance zone, identifying said incoming cell as non-conforming to said transmission control parameter and prioritizing said non-conforming cell using said early arrival curves defined for said transmission control parameter.