Multi-station physical layer communication over TP cable

• US 8,411,575 B2
• Filed: 05/24/2010
• Issued: 04/02/2013
• Est. Priority Date: 11/30/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Karam, Roger A.
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): LIU, JUNG
• Application Number:
  US12/785,882
• Publication Number:
  US 20100232298A1
• Time in Patent Office: 1,044 Days
• Field of Search: 370/203, 370229-240, 370241-253, 370254-258, 370298-306, 370351-356, 370357-395, 370/395.1, 370/395.2, 370/395.21, 370/395.3, 370/395.31, 370/395.32, 370/395.4, 370/395.41, 370/395.42, 370/395.43, 370/395.5, 370/395.52, 370/395.53, 370/395.54, 370/395.6, 370/395.61, 370396-411, 370412-429, 370503-520
• US Class Current: 370/241
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 67/125 involving control of end-device applications over a network
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

Wired data telecommunications networks can make advantageous use of a communications capability between and among more than two network devices. Such capabilities may be utilized in providing redundancy of data and/or inline power capabilities from a pair of network devices to a third network device receiving the redundant capability. Impedance modulated communications are provided in a wired data telecommunications network among at least a first, second and third network device coupled together via a Y device. The Y device couples the three network devices (higher order Y devices could couple more than three devices) allowing monitoring of communications and inline power provision so that one of the network devices may act in response to monitored conditions by communicating via impedance modulated communications with one or both of the other network devices.

Claims

1. A method for providing inline power between a first and a second network device associated with a first node of a network and a third network device associated with a second node of the network, in a wired data telecommunications network, the method comprising:

providing first inline power at a first voltage level from the first network device to the third network device;

providing second inline power at a second non zero voltage level different from the first voltage level from the second network device to the third network device; and

selecting one of the first inline power and the second inline power at the third network device in response to the voltage level associated therewith;

wherein the first voltage level is a first non-zero DC voltage;

wherein the second voltage level is a second non-zero DC voltage; and

wherein the first non-zero DC voltage is different from the second non-zero DC voltage.

2. A method for providing inline power between a first and a second network device associated with a first node of a network and a third network device associated with a second node of the network, in a wired data telecommunications network, the method comprising:

providing inline power at a first voltage level from the first network device to the third network device;

coupling the inline power from the first network device to the second network device through a Y-device;

monitoring the first network device at the second network device; and

detecting at the second network device a condition of the first network device;

initiating, responsive to said detecting, an impedance modulated signal from the second network device onto the wired data telecommunications network;

receiving at the first network device, the impedance modulated signal; and

backing off inline power provided between the first network device and the third network device in response to said receiving.

3. The method of claim 2, further comprising:

supplying inline power at a second voltage level from the second network device to the third network device.

4. The method of claim 3, wherein:

said second voltage level is lower than said first voltage level.

5. A method for providing inline power between a first and a second network device associated with a first node of a network and a third network device associated with a second node of the network, in a wired data telecommunications network, the method comprising:

providing inline power at a first voltage level from the first network device to the third network device;

coupling the inline power from the first network device to the second network device through a Y-device;

monitoring the first network device at the second network device; and

detecting at the second network device a condition of the first network device;

initiating, responsive to said detecting, an impedance modulated signal from the second network device onto the wired data telecommunications network;

receiving at the first network device, the impedance modulated signal; and

backing off inline power provided between the first network device and the third network device in response to said receiving.

6. The method of claim 5, further comprising:

supplying inline power at a second voltage level from the second network device to the third network device.

7. The method of claim 6, wherein:

said second voltage level is lower than said first voltage level.

8. The method of claim 6, wherein the second voltage level is non zero and different from the first voltage level.

9. The method of claim 5, wherein the providing inline power between a first and a second network device includes a common line portion for providing the second voltage level and the first voltage level to connect the first node to the second node.

10. A method for providing inline power between a first and a second network device associated with a first node of a network and a third network device associated with a second node of the network, in a wired data telecommunications network, the method comprising:

providing first inline power at a first voltage level from the first network device to the third network device;

providing second inline power at a second voltage level from the second network device to the third network device; and

selecting one of the first inline power and the second inline power at the third network device in response to the voltage level associated therewith;

wherein the first voltage level is a first non-zero DC voltage;

wherein the second voltage level is a second non-zero DC voltage; and

wherein the first non-zero DC voltage is different from the second non-zero DC voltage.

11. The method of claim 10, wherein a network cable extends along a network pathway between the first node and the second node to connect to a single network connector of the third network device of the second node;

wherein providing first inline power at the first voltage level from the first network device to the third network device includes conveying the first DC voltage through one set of conductors of the network cable to the single network connector of the third network device of the second node; and

wherein providing second inline power at the second voltage level from the second network device to the third network device includes conveying the second DC voltage through another set of conductors of the network cable to the single network connector of the third network device of the second node.

12. The method of claim 11, further comprising:

after selecting one of the first inline power and the second inline power at the third network device, exchanging data communications signals between the third network device and at least one of the first network device and the second network device through the network cable while the third network device receives inline power through the network cable.

13. The method of claim 12, wherein exchanging data communications signals between the third network device and at least one of the first network device and the second network device includes:

exchanging data communications signals between the third network device and the first network device during a first time period, and

exchanging data communications signals between the third network device and the second network device during a second time period after the first time period.

14. The method of claim 11, further comprising:

outputting a first copy of a data communications signal from the first network device, and concurrently outputting a second copy of the data communications signal from the second network device; and

wherein only one of the first copy of the data communications signal and the second copy of the data communications signal passes through the network cable to the single network connector of the third network device of the second node.

15. The method of claim 10, wherein a network pathway extends between the first node and the second node, the network pathway including (i) an intermediate device, (ii) a first network cable interconnected between a single network connector of the first network device of the first node and the intermediate device, (iii) a second network cable interconnected between a single network connector of the second network device of the first node and the intermediate device, and (iv) a third network cable interconnected between the intermediate device and a single network connector of the third network device of the second node;

wherein providing first inline power at the first voltage level from the first network device to the third network device includes conveying the first DC voltage through the first network cable, the intermediate device and the third network cable to the single network connector of the third network device of the second node; and

wherein providing second inline power at the second voltage level from the second network device to the third network device includes conveying the second DC voltage through the second network cable, the intermediate device and the third network cable to the single network connector of the third network device of the second node.

16. The method of claim 11, further comprising:

outputting a first copy of a data communications signal from the single network connector of the first network device of the first node to the intermediate device, and currently outputting a second copy of the data communications signal from the single network connector of the second network device of the first node to the intermediate device; and

wherein the intermediate device is constructed and arranged to convey only one of the first copy of the data communications signal and the second copy of the data communications signal through the third network cable to the single network connector of the third network device of the second node.