Per-flow rate control for an asynchronous metro packet transport ring
An asynchronous metropolitan packet transport ring having per-flow QoS. Asynchronous packetized data flow in one direction through a fiber optic loop. A number of Metropolitan Packet Switches (MPS) are coupled to the fiber optic loop. An MPS allows packetized data from an upstream MPS to flow to a downstream MPS over a segment of the fiber optic loop. The MPS also puts packetized data onto and pulls packetized data off of the fiber optic loop. Thereby, flows can access the fiber optic loop via the MPS's. The MPS's also regulate the data rates on a per-flow basis according to setup information supplied by a Ring Management System (RMS). If one segment of the fiber loop becomes overly congested, the MPS guarantees quality of service for those flows by deallocating available bandwidth from flows upstream to the point of congestion. Utilization of packet transport ring capacity is optimized by allocating any bandwidth that becomes available to active flows according to a pre-specified weighting scheme.
1. A metropolitan area packet ring, comprising: a fiber optic loop carrying asynchronous data packets, wherein the asynchronous data packets flow in one direction through the fiber optic loop; a plurality of metropolitan packet switches coupled to the fiber optic loop, wherein a metropolitan packet switch is comprised of: an I/O port coupled to the fiber optic loop which inserts packets of data onto the fiber optic loop and which pulls packets of data off the fiber optic loop; a processor coupled to the I/O port which separately regulates data packets transmitted over the fiber optic loop on a per-flow basis, and one or more devices to determine packetized data congestion corresponding to particular segments of the metropolitan area packet ring and to adjust flows upstream of a point of congestion.
2. The metropolitan area packet ring of claim 1 , wherein the processor regulates data rates to guarantee quality of service on a per-flow basis.
3. The metropolitan area packet ring of claim 2 , wherein the quality of service includes a variable bit rate with a minimum bandwidth.
4. The metropolitan area packet ring of claim 3 , wherein the quality of service includes a constant bit rate with a minimum delay.
5. The metropolitan area packet ring of claim 1 , wherein the processor controls data rates by which upstream flows are allowed to insert data packets onto the fiber optic loop.
6. The metropolitan area packet ring of claim 1 , wherein if bandwidth becomes available, the processor re-allocates available bandwidth amongst a plurality of flows.
7. The metropolitan area packet ring of claim 3 , further comprising a ring management system which initially assigns rate information for each of the flows.
8. The metropolitan area packet ring of claim 1 , wherein the data packets transmitted through the fiber loop comprise Ethernet packets.
9. The metropolitan area packet ring of claim 8 , wherein the Ethernet packets comprise 10 Gbit Ethernet.
10. The metropolitan area packet ring of claim 1 further comprising another fiber optic ring, wherein data packets flow in different directions through the two fiber optic rings.
11. In a metropolitan area packet ring having a plurality of switching devices through which a plurality of devices are coupled to the metropolitan area packet ring, a method for managing packetized traffic flowing asynchronously through the metropolitan area packet ring, comprising the steps of: inserting packets onto the metropolitan area packet ring; removing packets from the metropolitan area packet ring; controlling rates by which the packets are allowed to be inserted onto the packet ring on a per-flow basis ; and determining packetized data congestion corresponding to particular segments of the metropolitan area packet ring; and adjusting flows upstream of a point of congestion in order to guarantee that quality of service is being met.
12. The method of claim 11 further comprising the step of guaranteeing quality of service on a per-flow basis.
13. The method of claim 12 , wherein the quality of service includes a variable bit rate with a minimum bandwidth.
14. The method of claim 12 , wherein the quality of service includes a constant bit rate with a minimum delay.
15. The method of claim 11 further including the steps of determining packetized data congestion corresponding to particular segments of the metropolitan area packet ring; adjusting flows upstream of a point of congestion in order to guarantee that quality of service is being met.
16. The method of claim 11 further comprising the step of allocating available bandwidth to flows according to a pre-determined scheme.
17. The method of claim 11 , wherein the packetized data flowing through the fiber optic loop is comprised of Ethernet packets.
18. The method of claim 17 , wherein the fiber optic loop is comprised of 10 Gbit Ethernet.
19. A device for controlling packetized data in a packet ring, comprising: a first port used to insert data packets onto the packet ring; a second port for taking data packets off from the packet ring; a processor coupled to the first port which controls data packets flowing asynchronously through the packet ring, wherein the processor controls a rate by which data packets are allowed to be inserted onto the packet ring by determining packetized data congestion corresponding to particular segments of the metropolitan area packet ring; and causing flows upstream of a point of congestion to be adjusted in order to guarantee that quality of service is being met.
20. The device of claim 19 , wherein rates by which data packets are allowed to be inserted onto the packet ring are controlled on a per-flow basis.
21. The device of claim 19 , wherein the processor adjusts the rates such that quality of service is guaranteed.
22. The device of claim 21 , wherein quality of service includes a variable bit rate with a minimum bandwidth.
23. The device of claim 21 , wherein quality of service includes a constant bit rate with a minimum delay.
24. The device of claim 21 , wherein quality of service is guaranteed by decreasing a data rate by which an upstream flow is allowed to insert its data packets onto the packet ring.
25. The device of claim 19 , wherein if bandwidth on the packet ring becomes available, the processor allocates available bandwidth on a per-flow basis.
26. The device of claim 19 , wherein the packet ring is comprised of a fiber loop.