METHOD OF SUPPORTING POWER CONTROL IN A COMMUNICATION NETWORK

• US 20120170592A1
• Filed: 07/08/2010
• Published: 07/05/2012
• Est. Priority Date: 07/08/2010
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Europe Ltd
• Inventors: Dudkowski, Dominique, Hasselmeyer, Peer
• Granted Patent: US 9,106,580 B2
• Time in Patent Office: Days
• US Class Current: 370/419
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 41/0833 for reduction of network energy consumption
• CPC Class Codes: H04L 41/342 between virtual entities, e.g. orchestrators, SDN or NFV entities
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of supporting power control in a communication network, the network including a plurality of network elements (1) that perform packet forwarding, wherein each network element (1) includes one or more ports—element ports (2)—, is characterized in the steps of assigning a flow table (4) to each of the network elements (1), wherein the flow table (4) includes flow entries (5) that specify via which element ports (2) to forward packets the network element (1) receives, deriving target sets from the flow tables (4), wherein a target set characterizes either a network element (1) as a whole—element target set—or an individual element port (2)—port target set—in terms of its utilization, and based on changes in the respective target sets, deciding on the enforcement of power states on the network elements (1) and/or the element ports (2).

Claims

1. Method of supporting power control in a communication network, said network including a plurality of network elements (1) that perform packet forwarding, wherein each network element (1) includes one or more ports—

element ports (2)—

,

characterized in the steps of

assigning a flow table (4) to each of said network elements (1), wherein said flow table (4) includes flow entries (5) that specify via which element ports (2) to forward packets the network element (1) receives,

deriving target sets from said flow tables (4), wherein a target set characterizes either a network element (1) as a whole—

element target set—

or an individual element port (2)—

port target set—

in terms of its utilization, and based on changes in the respective target sets, deciding on the enforcement of power states on said network elements (1) and/or said element ports (2).

2. Method according to claim 1, wherein the target set of an element port (2) of a network element (1)—

port target set—

includes all flow entries (5) of said network element (1) that have element port (2) as egress port together with all flow entries of other network elements that are connected to said network element'"'"'s (1) element port (2) via an element port being specified as egress port in said flow entries (5).

3. Method according to claim 1, wherein the target set of a network element (1)—

element target set—

includes the flow entries (5) of all element ports (2) of said network element (1).

4. Method according to claim 1, wherein an element port (2) is deactivated in case the corresponding port target set becomes empty and/or wherein a network element (1) is deactivated in case the corresponding element target set becomes empty.

5. Method according to claim 1, wherein a centralized power control is provided that, upon relevant changes of a port target set and/or an element target set, initiates the activation/deactivation of the corresponding element port (2) and/or network element (1).

6. Method according to claim 5, wherein said centralized power control calculates a routing path, identifies network elements (1) on said routing path, and stores a local copy of the flow tables (5) of each of said network elements (1).

7. Method according to claim 6, wherein said centralized power control calculates changes in said flow tables (5) that need to be applied to establish said routing path, and selects those network elements (1) and element ports (2) for which the element target set and port target set, respectively, have become non-empty.

8. Method according to claim 6, wherein said centralized power control contacts each selected network element (1) and element port (2) to initiate start up.

9. Method according to claim 5, wherein a packet intercepted by a network element (1) on its routing path towards a destination node is buffered by said network element (1) until it receives a signaling message from said centralized power control indicating that all network elements (1) of said routing path are activated.

10. Method according to claim 5, wherein a first network element (1) at which a packet, which is to be transmitted within said network, is intercepted buffers said packet and asks said centralized controller to find an appropriate routing path through said network.

11. Method according to claim 10, wherein said first network element (1) contacts all network elements (1) on said routing path, communicating routing table entries to them.

12. Method according to claim 10, wherein said first element (1) waits for incoming notifications about all network elements (1) on said routing path being operational and it then releases said buffered packet into said network.

13. Method according to claim 10, wherein element target sets and/or port target sets are updated by said network elements (1) on said routing path individually according to the routing information received from said first network element (1).

14. Method according to claim 1, wherein a network element (1), in case a flow entry (5) is removed from its flow table (4), adjusts its port target set and element target set, determines the set of adjacent network elements whose target sets are affected by said removed flow entry (5), and signals to all affected adjacent elements the removed flow entry (5).

15. Method according to claim 1, wherein flow entries (5) are removed from flow tables (4) by the definition of flow entry timeouts.

16. Method according to claim 1, wherein flow entries (5) are removed from flow tables (4) upon explicit request from said centralized power control.

17. Method according to claim 1, wherein, in case of a network element (1) deactivation, an idling period is introduced that has to elapse before said network element'"'"'s (1) deactivation procedure is finally initiated.

18. Method according to claim 17, wherein said idling period is reset in case a flow entry (5) is created in the meantime that results in the creation of an element target set for said network element (1).

19. Method according to claim 17, wherein said idling period is controlled by said centralized power control or within the respective network element (1) directly.

20. Method according to claim 5, wherein said centralized power control duplicates or mimics network element (1) state changes relevant to element target sets and/or port target sets.

21. Method according to claim 20, wherein said centralized power control, based on information about hard flow entry timeouts, removes flow entries (5) from its local copy of network elements'"'"' (1) flow tables (4).

22. Method according to claim 1, wherein soft flow entry timeouts of different flow entries (5) of a flow table (4) are synchronized with each other by introducing a soft timeout clock cycle.

23. Method according to claim 1, wherein hard timeouts are synchronized with soft timeouts by making the hard timeout interval a multiple of said soft timeout clock cycle.

24. Method according to claim 1, wherein said network elements (1) are equipped with Wake-on-LAN capabilities.

25. Method according to claim 1, wherein said network elements (1) are network routers/switches that make use of routing/switching tables containing routing/switching entries.