DISTRIBUTED RESCHEDULING OF BOUNDED FLOWS IN A TIME SENSITIVE NETWORK

• US 20160021017A1
• Filed: 07/18/2014
• Published: 01/21/2016
• Est. Priority Date: 07/18/2014
• Status: Active Grant

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Thubert, Pascal, Vasseur, Jean-Philippe, Wetterwald, Patrick
• Granted Patent: US 9,319,332 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

In one embodiment, a device determines that a latency between a receive timeslot of a channel hopping schedule of the device and a transmit timeslot of the channel hopping schedule is greater than a latency threshold for a particular traffic flow to be received during the receive timeslot. The device requests an additional transmit timeslot for the channel hopping schedule from a parent node of the device in the network. The device receives an indication of a newly allocated transmit timeslot for the channel hopping schedule from the parent node. The device maps the receive timeslot to one of the transmit timeslots of the channel hopping schedule, wherein the particular traffic flow is to be forwarded to a second device during the mapped transmit timeslot.

Claims

1. A method, comprising:

determining, by a device in a network, that a latency between a receive timeslot of a channel hopping schedule of the device and a transmit timeslot of the channel hopping schedule is greater than a latency threshold for a particular traffic flow to be received during the receive timeslot;

requesting, by the device, an additional transmit timeslot for the channel hopping schedule from a parent node of the device in the network;

receiving, at the device, an indication of a newly allocated transmit timeslot for the channel hopping schedule from the parent node; and

mapping, by the device, the receive timeslot to one of the transmit timeslots of the channel hopping schedule, wherein the particular traffic flow is to be forwarded to a second device during the mapped transmit timeslot.

2. The method as in claim 1, wherein the receive timeslot is mapped to the newly allocated transmit timeslot, the method further comprising:

locking the mapping between the receive timeslot and the newly allocated transmit timeslot for periodic transmission of the particular traffic flow to the second device.

3. The method as in claim 2, wherein the mapping between the receive timeslot and the newly allocated transmit timeslot is locked based on a jitter requirement associated with the particular traffic flow.

4. The method as in claim 2, further comprising:

determining that the traffic flow is not present in the receive timeslot; and

, in response,

unlocking the mapping between the receive timeslot and the newly allocated transmit timeslot.

5. The method as in claim 4, further comprising:

monitoring unlocked transmit timeslots of the channel hopping schedule, wherein the unlocked transmit timeslots do not have locked mappings with corresponding receive timeslots in the channel hopping schedule;

identifying a least used transmit timeslot from among the unlocked transmit timeslots of the channel hopping schedule, in response to the mapping between the receive timeslot and the newly allocated transmit timeslot being unlocked; and

requesting that the parent node de-allocate the least used transmit timeslot from the channel hopping schedule.

6. The method as in claim 1, further comprising:

receiving an indication of a priority and a periodicity of the particular traffic flow, wherein the latency threshold is based on the priority of the particular traffic flow, and wherein the receive timeslot is mapped to the mapped transmit timeslot based on the periodicity of the particular traffic flow.

7. The method as in claim 1, further comprising:

inspecting packets of the particular traffic flow;

determining a priority of the particular traffic flow based on the inspected packets; and

determining a periodicity of the particular traffic flow based on the inspected packets,

wherein the latency threshold is based on the priority and the periodicity of the particular traffic flow.

8. The method as in claim 1, wherein the latency threshold is a single hop latency threshold associated with the device.

9. The method as in claim 1, wherein the latency threshold corresponds to a maximum allowed deviation from a path latency for the particular traffic flow.

10. The method as in claim 1, wherein the latency between the receive timeslot and the newly allocated timeslot is below the latency threshold.

11. An apparatus, comprising:

one or more network interfaces to communicate with a network;

a processor coupled to the network interfaces and configured to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

determine that a latency between a receive timeslot of a channel hopping schedule of the apparatus and a transmit timeslot of the channel hopping schedule is greater than a latency threshold for a particular traffic flow to be received during the receive timeslot;

request an additional transmit timeslot for the channel hopping schedule from a parent node of the apparatus in the network;

receive an indication of a newly allocated transmit timeslot for the channel hopping schedule from the parent node; and

map the receive timeslot to one of the transmit timeslots of the channel hopping schedule, wherein the particular traffic flow is to be forwarded to a second device during the mapped transmit timeslot.

12. The apparatus as in claim 11, wherein the receive timeslot is mapped to the newly allocated transmit timeslot, wherein the process when executed is further operable to:

lock the mapping between the receive timeslot and the newly allocated transmit timeslot for periodic transmission of the particular traffic flow to the second device.

13. The apparatus as in claim 12, wherein the mapping between the receive timeslot and the newly allocated transmit timeslot is locked based on a jitter requirement associated with the particular traffic flow.

14. The apparatus as in claim 12, wherein the process when executed is further operable to:

determine that the traffic flow is not present in the receive timeslot; and

, in response,

unlock the mapping between the receive timeslot and the newly allocated transmit timeslot.

15. The apparatus as in claim 14, wherein the process when executed is further operable to:

monitor unlocked transmit timeslots of the channel hopping schedule, wherein the unlocked transmit timeslots do not have locked mappings with corresponding receive timeslots in the channel hopping schedule;

identify a least used transmit timeslot from among the unlocked transmit timeslots of the channel hopping schedule, in response to the mapping between the receive timeslot and the newly allocated transmit timeslot being unlocked; and

request that the parent node de-allocate the least used transmit timeslot from the channel hopping schedule.

16. The apparatus as in claim 11, wherein the process when executed is further operable to:

receive an indication of a priority and a periodicity of the particular traffic flow, wherein the latency threshold is based on the priority of the particular traffic flow, and wherein the receive timeslot is mapped to the mapped transmit timeslot based on the periodicity of the particular traffic flow.

17. The apparatus as in claim 11, wherein the process when executed is further operable to:

inspect packets of the particular traffic flow;

determine a priority of the particular traffic flow based on the inspected packets; and

determine a periodicity of the particular traffic flow based on the inspected packets,

wherein the latency threshold is based on the priority and the periodicity of the particular traffic flow.

18. The apparatus as in claim 11, wherein the latency threshold is a single hop latency threshold associated with the device.

19. The apparatus as in claim 11, wherein the latency threshold corresponds to a maximum allowed deviation from a path latency for the particular traffic flow.

20. The apparatus as in claim 11, wherein the latency between the receive timeslot and the newly allocated timeslot is below the latency threshold.

21. A tangible, non-transitory, computer-readable media having software encoded thereon, the software when executed by a processor operable to:

determine that a latency between a receive timeslot of a channel hopping schedule and a transmit timeslot of the channel hopping schedule is greater than a latency threshold for a particular traffic flow to be received during the receive timeslot;

request an additional transmit timeslot for the channel hopping schedule from a parent node;

receive an indication of a newly allocated transmit timeslot for the channel hopping schedule from the parent node; and

map the receive timeslot to one of the transmit timeslots of the channel hopping ii schedule, wherein the particular traffic flow is to be forwarded to a second device during the mapped transmit timeslot.