Method and switch for managing traffic in transport network

• US 10,567,290 B2
• Filed: 04/07/2016
• Issued: 02/18/2020
• Est. Priority Date: 02/08/2016
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Cavaliere, Fabio, Bottari, Giulio, Stracca, Stefano
• Primary Examiner(s): Hoang, Thai D
• Application Number:
  US16/074,178
• Publication Number:
  US 20190260681A1
• Time in Patent Office: 1,412 Days
• Field of Search: 370230-2381, 370352-356, 370389-39543
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/66 Layer 2 routing, e.g. in Ethernet based MAN's
• CPC Class Codes: H04L 47/18 End to end
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric

Abstract

A method for managing traffic of a plurality of packets in a plurality of packet flows transmitted using a time-slotted interface. The packet flows traverse a plurality of switches of a transport network according to an assigned path from a source node to a destination node. The method comprises determining (202) an end-to-end latency of a plurality of packets traversing a current switch in packet flows and assigning (204) priority to packets to the packets traversing the current switch, wherein a priority value of a packet depends on the determined end-to-end latency of said packets. The method further comprises allocating (206) a time slot in an output interface of the current switch to the packet having the highest priority value among the packets competing for said time slot.

Claims

1. A method for managing traffic of a plurality of packets in a plurality of packet flows transmitted using a time-slotted interface, each of the packet flows traversing a plurality of switches of a transport network according to an assigned path from a source node to a destination node, the method comprising:

determining an end-to-end latency of a plurality of packets traversing a current switch in packet flows, wherein determining the end-to-end latency comprises, for each packet flow;

determining an accumulated latency from the source node of the packet flow to the current switch;

estimating a forecasted latency from the current switch to the destination node of the packet flow based on the assigned path of the packet flow;

calculating the end-to-end latency of the packet flow as a sum of the accumulated latency value and forecasted latency value for the packet flow;

assigning priority values to the packets traversing the current switch, wherein a priority value of a packet depends on the determined end-to-end latency of the packets; and

allocating a time slot in an output interface of the current switch to the packet having the highest priority value among the packets competing for the time slot.

2. The method of claim 1, wherein the estimating the forecasted latency comprises determining an accumulated latency from the destination node to the current switch based on packets travelling from the destination node to the current switch.

3. The method of claim 1, wherein the determined end-to-end latency includes latency introduced by the current switch.

4. The method of claim 1, wherein the determining the end-to-end latency comprises considering switching delay introduced by the switches along the path and ignoring propagation delay.

5. The method of claim 1, wherein the assigning priority values to the packets traversing the current switch comprises applying weighting factors based on class of service associated with the packets.

6. The method of claim 1, wherein operations of the method are applied separately within each class of service associated with the packets.

7. The method of claim 1, wherein operations of the method are applied to packets having the same class of service.

8. The method of claim 1, wherein end points of the traffic traversing the plurality of switches include at least one baseband unit (BBU) and a plurality of remote radio units (RRUs) or Radio Baseband Units (RBUs).

9. The method of claim 1, wherein packets of the packet flows are transported in the transport network encapsulated as payload in Ethernet frames.

10. The method of claim 1, further comprising recording, in a dedicated information field associated with a packet traversing the current switch, the determined end-to-end latency for this packet.

11. A switch for forwarding packets to a network node of a transport network, the packets traversing the transport network according to an assigned path from a source node to a destination node, the switch comprising:

a plurality of input/output ports connected to a switching matrix,

processing circuitry operatively connected to the plurality of input/output ports;

memory containing instructions executable by the processing circuitry whereby the switch is operative to;

determine end-to-end latency of a plurality of packets traversing the switch in packet flows, wherein to determine the end-to-end latency the switch is operative to, for each packet flow;

determine an accumulated latency from the source node of the packet flow to the switch;

estimate a forecasted latency from the switch to the destination node of the packet flow based on the assigned path of the packet flow;

calculate the end-to-end latency of the packet flow as a sum of the accumulated latency value and forecasted latency value for the packet flow;

assign priority values to packets traversing the switch, wherein a priority value of a packet depends on the determined end-to-end latency of the packet; and

allocate a time slot in an output interface of the switch to the packet having the highest priority value among the packets competing for the time slot.

12. The switch of claim 11, wherein the instructions are such that the switch is operative, in estimating the forecasted latency, to determine an accumulated latency from the destination node to the switch based on packets travelling from the destination node to the switch.

13. The switch of claim 11, wherein the determined end-to-end latency includes latency introduced by the switch.

14. The switch of claim 11, wherein the instructions are such that the switch is operative, in assigning priority values to the packets traversing the switch, to apply weighting factors based on class of service associated with the packets.

15. The switch of claim 11, wherein end points of the traffic traversing the plurality of switches include at least one baseband unit (BBU) and a plurality of remote radio units (RRUs) or Radio Baseband Units (RBUs).

16. The switch of claim 11, wherein the instructions are such that the switch is operative to record, in a dedicated information field of a packet traversing the switch, the determined end-to-end latency for this packet.

17. A centralized network element for orchestrating forwarding of packets in a transport network, the packets traversing the transport network according to an assigned path from a source node to a destination node, the centralized network element comprising:

a communication interface for connecting to a plurality of switches in the network;

processing circuitry operatively connected to the communication interface;

memory containing instructions executable by the processing circuitry whereby the centralized network element is operative to;

determine end-to-end latency of a plurality of packets traversing a switch in packet flows, wherein to determine the end-to-end latency the centralized network element is operative to, for each packet flow;

determine an accumulated latency from the source node of the packet flow to the switch;

estimate a forecasted latency from the switch to the destination node of the packet flow based on the assigned path of the packet flow;

calculate the end-to-end latency of the packet flow as a sum of the accumulated latency value and forecasted latency value for the packet flow;

instruct the switch to assign priority values to packets traversing the switch, wherein a priority value of a packet depends on the determined end-to-end latency of the packet; and

instruct the switch to allocate a time slot in an output interface of the switch to the packet having the highest priority value among the packets competing for the time slot.

18. A transport network, comprising:

a plurality of switches connecting at least one baseband unit (BBU) and a plurality of remote radio units (RRUs) or Radio Baseband Units (RBUs);

wherein the plurality of switches are configured to manage traffic of a plurality of packets in a plurality of packet flows transmitted using a time-slotted interface, the packet flows traversing the plurality of switches of the transport network according to an assigned path from a source node to a destination node;

wherein the plurality of switches are configured to manage the traffic by;

determining an end-to-end latency of a plurality of packets traversing a current switch in packet flows, wherein determining the end-to-end latency comprises, for each packet flow;

determining an accumulated latency from the source node of the packet flow to the current switch;

estimating a forecasted latency from the current switch to the destination node of the packet flow based on the assigned path of the packet flow;

calculating the end-to-end latency of the packet flow as a sum of the accumulated latency value and forecasted latency value for the packet flow;

assigning priority values to the packets traversing the current switch, wherein a priority value of a packet depends on the determined end-to-end latency of the packets; and

allocating a time slot in an output interface of the current switch to the packet having the highest priority value among the packets competing for the time slot.