Flow control and congestion management for random scheduling in time-domain wavelength interleaved networks
View Patent ↗Flow control techniques are disclosed for use in data communications networks such as those implementing a time-domain wavelength interleaved network (TWIN) architecture or other suitable architectures. Such techniques may provide for congestion management and scheduling for asynchronous traffic. For example, in one aspect, a technique comprises collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network, and adjusting a transmission rate of the node in response to at least a portion of the collected information such that the node operates under a substantially stable transmission schedule with respect to asynchronous data bursts. The transmission rate adjusting step/operation may further comprise adjusting the transmission rate such that the node operates under a substantially fair transmission schedule. The node may operate under a random transmission schedule.
1. A method, comprising the steps of:
collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network;
computing a data burst allocation indicator value from at least a portion of the collected information; and
adjusting a transmission rate of the node in response to the data burst allocation indicator value such that the node operates under a stable transmission schedule with respect to asynchronous data bursts.
2. The method of claim 1 , wherein the transmission rate adjusting step further comprises adjusting the transmission rate such that the node operates under a fair transmission schedule.
3. The method of claim 1 , wherein the transmission rate adjusting step further comprises adjusting the transmission rate such that the node operates under a random transmission schedule.
4. The method of claim 1 , wherein the optical-based communications network is a time-domain wavelength interleaved network.
5. A method, comprising the steps of:
collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network; and
adjusting a transmission rate of the node in response to at least a portion of the collected information such that the node operates under a stable transmission schedule with respect to asynchronous data bursts;
wherein the information collecting step further comprises collecting, for a given control interval, feedback information representing the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval.
6. The method of claim 5 , wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts received by the node from one or more other nodes in the network in the given control interval.
7. The method of claim 6 , wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts transmitted by the node before the given control interval over a time period equivalent to a round trip propagation delay between the node and a given destination node in the network.
8. The method of claim 7 , further comprising the step of computing a data burst allocation indicator from the collected information.
9. The method of claim 8 , wherein the data burst allocation indicator is a local estimate representing an indicator of collision servicing by the transmission schedule of the node.
10. A method, comprising the steps of:
collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network;
adjusting a transmission rate of the node in response to at least a portion of the collected information such that the node operates under a stable transmission schedule with respect to asynchronous data bursts;
wherein the information collecting step further comprises collecting, for a given control interval, feedback information representing the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts received by the node from one or more other nodes in the network in the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts transmitted by the node before the given control interval over a time period equivalent to a round trip propagation delay between the node and a given destination node in the network; and
computing a data burst allocation indicator from the collected information;
wherein the transmission rate adjusting step further comprises decreasing the transmission rate when the data burst allocation indicator is greater than a given threshold value and the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval is greater than or equal to the number of data bursts received by the node from one or more other nodes in the network in the given control interval.
11. A method, comprising the steps of:
collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network;
adjusting a transmission rate of the node in response to at least a portion of the collected information such that the node operates under a stable transmission schedule with respect to asynchronous data bursts;
wherein the information collecting step further comprises collecting, for a given control interval, feedback information representing the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts received by the node from one or more other nodes in the network in the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts transmitted by the node before the given control interval over a time period equivalent to a round trip propagation delay between the node and a given destination node in the network; and
computing a data burst allocation indicator from the collected information;
wherein the transmission rate adjusting step further comprises increasing the transmission rate when the data burst allocation indicator is greater than a given threshold value and the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval is less than the number of data bursts received by the node from one or more other nodes in the network in the given control interval.
12. A method, comprising the steps of:
collecting information at a node of an optical-based communications network, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network;
adjusting a transmission rate of the node in response to at least a portion of the collected information such that the node operates under a stable transmission schedule with respect to asynchronous data bursts;
wherein the information collecting step further comprises collecting, for a given control interval, feedback information representing the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts received by the node from one or more other nodes in the network in the given control interval;
wherein the information collecting step further comprises collecting, for a given control interval, information representing the number of data bursts transmitted by the node before the given control interval over a time period equivalent to a round trip propagation delay between the node and a given destination node in the network; and
computing a data burst allocation indicator from the collected information;
wherein the transmission rate adjusting step further comprises increasing the transmission rate when the data burst allocation indicator is less than or equal to a given threshold value and the number of collisions that occurred with respect to transmissions of data bursts by the node previous to the given control interval is equal to the number of data bursts received by the node from one or more other nodes in the network in the given control interval.
13. A method, comprising the steps of:
collecting information at a node of a time-domain wavelength interleaved network, wherein at least a portion of the collected information pertains to congestion in the network;
computing a data burst allocation indicator value from at least a portion of the collected information; and
scheduling, at the node, transmission of asynchronous data bursts from the node in response to the data burst allocation indicator value.
14. The method of claim 13 , wherein the scheduling step comprises a random transmission schedule.
15. Apparatus, comprising:
a memory; and
a processor, associated with a node of an optical-based communications network, coupled to the memory and operative to: (i) collect information at the node, wherein at least a portion of the collected information pertains to congestion in the optical-based communications network; (ii) compute a data burst allocation indicator value from at least a portion of the collected information; and
(iii) adjust a transmission rate of the node in response to the data burst allocation indicator value such that the node operates under a stable transmission schedule with respect to asynchronous data bursts.
16. The apparatus of claim 15 , wherein the transmission rate adjusting operation further comprises adjusting the transmission rate such that the node operates under a fair transmission schedule.
17. The apparatus of claim 15 , wherein the transmission rate adjusting operation further comprises adjusting the transmission rate such that the node operates under a random transmission schedule.
18. The apparatus of claim 15 , wherein the information collecting operation and the transmission rate adjusting operation are performed, for the given control interval, for one or more node pairs formed by the node and one or more destination nodes in the network.
19. The apparatus of claim 15 , wherein the optical-based communications network is a time-domain wavelength interleaved network.
20. Apparatus, comprising:
a memory; and
a processor, associated with a node of a time-domain wavelength interleaved network, coupled to the memory and operative to: (i) collect information at the node, wherein at least a portion of the collected information pertains to congestion in the network; (ii) compute a data burst allocation indicator value from at least a portion of the collected information; and (iii) randomly schedule, at the node, transmission of asynchronous data bursts from the node in response to the data burst allocation indicator value.