Method and a device for implicit differentiation of quality of service in a network

1. A device for processing packets of flows on a network link, the device comprising:

scheduling means for scheduling packets of flows in a queue in accordance with a fair queuing with priority algorithm, the scheduling means being configured to schedule as priority packets any packets of flows in the queue that are not identified in a list of active flows and as non-priority packets any packets of flows that are already identified in the list of active flows;

means for writing flows in and erasing flows from the list of active flows as a function of the arrival and departure of packets of the flows, said means being configured to erase from the list of active flows a flow which has not had any packets in the queue for a certain time period, and thereby assigning priority to the packets of the flows for which a bit rate is below a dynamic threshold, the dynamic threshold being determined by traffic conditions; and

admission control means for controlling admission of said packets into the device in accordance with admission criteria;

wherein the scheduling means sends the admission control means admissibility condition data including a fair bit rate value that represents the bit rate achieved by a data flow that always has packets to send, and a priority load value which is a sum of the lengths of priority packets transmitted in a certain time period divided by the duration of that time period.

2. The device according to claim 1 , wherein the admission control means comprise means for interrogating a list of protected flows for each incoming packet.

3. The device according to claim 2 , further comprising means for erasing flows for which the time elapsed since the last packet was received exceeds a threshold value from the list of protected flows.

4. The device according to claim 2 , wherein the admission control means comprise means for determining if the admission criteria are satisfied if a packet belongs to a flow that is not in the list of protected flows.

5. The device according to claim 2 , comprising means for entering a new flow in the list of protected flows if the admission criteria are satisfied.

6. The device according to claim 1 , wherein the scheduling means schedule the packets in a PIFO queue.

7. The device according to claim 6 , wherein a pointer P identifies the last of the priority packets at the head of the queue.

8. The device according to claim 7 , further configured to employ the list of active flows containing the identifiers of the active flows and wherein a time stamp is used for scheduling packets.

9. The device according to claim 8 , further comprising means for measuring congestion.

10. The device according to claim 9 , wherein congestion measurements are carried out as a function of a local time, a number of priority packet bytes transmitted during a current measurement period, and a number of bytes that a dummy flow could send in said current measuring period.

11. The device according to claim 6 , comprising means for determining whether the PIFO queue is empty.

12. The device according to claim 1 , further comprising discrimination means for distinguishing classes of service at admission control level.

13. The device according to claim 1 , wherein the flows are identified by a hashing function applied to address attributes.

14. A method of treating packets of flows on a network link and ensuring a quality of service without explicitly distinguishing between real-time flows and data flows, the method comprising;

a scheduling step for scheduling packets of flows in a queue in accordance with a fair queuing with priority algorithm, the scheduling step scheduling as priority packets any packets in the queue that are not identified in a list of active flows and as non-priority packets any packets of flows that are already identified in the list of active flows;

writing flows in and erasing flows from the list of active flows as a function of the arrival and departure of packets of the flows, wherein a flow which has not has not had any packets in the queue for a certain time period erased from the list of active flows, and thereby assigning priority to the packets of the flows for which a bit rate is below a dynamic threshold, the dynamic threshold being determined by traffic conditions;

an admission control step for controlling the admission of said packets into a device for processing said packets in accordance with admission criteria; and

sending admissibility conditions data to a means for controlling admission of the data,

wherein the admissibility conditions data include:

a fair bit rate value that represents the bit rate achieved by a data flow that always has packets to send, and

a priority load value which is a sum of the lengths of priority packets transmitted in a certain time period divided by the duration of that time period.

15. The method according to claim 14 , wherein the admission control step includes interrogating a list of protected flows for each incoming packet.

16. The method according to claim 15 , wherein flows for which the time elapsed since the last packet was received exceeds a threshold value are erased from the list of protected flows.

17. The method according to claim 15 , comprising a step for determining if the admission criteria are satisfied if a packet belongs to a flow that is not in the list of protected flows.

18. The method according to claim 15 , comprising a step of entering a new flow in the list if the admission criteria are satisfied.

19. The method according to claim 14 , wherein the scheduling means schedule packets in a PIFO queue.

20. The method according to claim 19 , wherein a pointer P identifies the last of the priority packets at the head of the queue.

21. The method according to claim 20 , further employing the list of active flows containing the identifiers of the flows and wherein a time stamp is used for scheduling packets.

22. The method according to claim 21 , further comprising congestion measurement step for measuring congestion.

23. The method according to claim 22 , wherein congestion measurements are carried out as a function of a local time, a number of priority packet bytes transmitted during a current measurement period, and a number of bytes that a dummy flow could send in said current measurement period.

24. The method according to claim 19 , including a step for determining whether the PIFO queue is empty.

25. The method according to claim 14 , wherein a signal relating to the loss of packets is sent to a user.

26. The method according to claim 14 , further comprising discriminating classes of service at admission control level.

27. The method according to claim 14 , wherein load sharing of flows over a plurality of links is effected with the aid of a function of address attributes including a free portion of a flow identifier.

28. A device for processing packets of flows on a network link, the device comprising:

scheduling means for scheduling packets in a queue as a function of a priority based on analyzing the incoming bit rate of the flows relative to a fair bit rate and in accordance with a fair queuing with priority algorithm; and

admission control means for controlling admission of said packets into the device in accordance with admission criteria,

wherein the admissibility condition data includes:

a fair bit rate value that represents the bit rate achieved by a data flow that always has packets to send, and

a priority load value, which is sum of the lengths of priority packets transmitted in a certain time period divided by the duration of that time period.

29. A method of treating packets of flows on a network link, the method comprising:

a scheduling step for scheduling packets in a queue as a function of a priority based on analyzing the incoming bit rate of the flows relative to a fair bit rate and in accordance with a fair queuing with priority algorithm;

an admission control step for controlling the admission of said packets into a device for processing said packets in accordance with admission criteria; and

a step of sending admissibility conditions to a means for controlling admission of the data;

wherein the admissibility conditions data include:

a fair bit rate value that represents the bit rate achieved by a data flow that always has packets to send, and

a priority load value, which is sum of the lengths of priority packets transmitted in a certain time period divided by the duration of that time period.