Self-healing data network and network node controller

• US 5,113,398 A
• Filed: 08/01/1989
• Issued: 05/12/1992
• Est. Priority Date: 06/01/1989
• Status: Expired due to Fees

• Current Assignee: Eurotherm Drives Inc. (Schneider Electric SE)
• Original Assignee: Shackleton System Drives Corporation (Schneider Electric SE)
• Inventors: Howes, Nicholas J.
• Primary Examiner(s): Beausoliel, Robert W.
• Application Number:
  US07/360,024
• Time in Patent Office: 1,015 Days
• Field of Search: 371/8.2, 371/11.2, 371/11.1, 371/8.1, 371/20.6, 371/20.1, 375/38, 375/40, 375/100, 370/16, 370/16.1, 370/85.12, 370/100.1, 455/8, 340/825.01, 340/827, 340/825.03
• US Class Current: 714/4.21
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085

Abstract

A self-healing data network and network node controller. Data transmission of data cells to form message permitting self-clocking operation of each node and elastic buffering implemented to allow receipt of messages without regard to the phase of messages allows asynchronous operation of each node relative to other nodes. Fault detection and network self-healing are performed by each node independently of other nodes.

Claims

1. A data network comprising:

a. a plurality of nodes asynchronously sending and receiving data signals,

b. a first data pathway for connecting said nodes,

c. a second data path for connecting said nodes,

d. means located at each node for detecting a fault in either of said first or said second data pathways, such means operating independently of all other said nodes, and

e. means located at each node for switching between said first and said second data pathways upon the detection of a fault, such means operating independently of all other said nodes.

2. A data network according to claim 1, further comprising, at each siad node, means for elastically buffering received data signals and means for clocking data signals independently of each of the other said nodes.

3. A data network according to claim 1, wherein each node further comprises:

a. means for receiving data signals independent of phase of said data signals, and

b. recognizing data signals independent of clocking at any other node.

4. A data network according to claim 1, wherein said first and said second data pathways are comprised of fiber optic cables.

5. A data network according to claim 1, wherein said first and said second data pathways are comprised of wire connectors.

6. A data network according to claim wherein each node further comprises:

a. means for clocking independent of all other nodes,

b. means for sending data signals on said first data pathway,

c. means for sending data signals on said second data pathway,

d. means for receiving data signals on said first data pathway,

e. means for receiving data signals on said second data pathway,

f. means for detecting the absence of data signals on said first data pathway which operate independently of all other nodes,

g. means for detecting the absence of data signals on said second data pathway which operate independently of all other nodes,

h. means for switching between said first and said second data pathways upon the detection of the absence of data signals,

i. means for elastically buffering received data signals from said first data pathway, and

j. means for elastically buffering received data signals from said second data pathway.

7. A data network according to claim 6, wherein each means (a) through (j) is implemented in an integrated circuit at each node.

8. A data network node comprising:

a. means for receiving data signals from a first data pathway, independent of timing functions external thereto,

b. means for receiving data signals from a second data pathway, independent of timing functions external thereto,

c. means for sending data signals on said first data pathway,

d. means for sending data signals on said second data pathway,

e. means for storing said received data signals from said first data pathway independent of the phase of data signals sent on said first data pathway,

f. means for storing said received data signal from said second data pathway independent of the phase of data signals sent on said second data pathway,

g. means for selecting between data signals from said first data pathway and said second data pathway,

h. means for communicating said selected signals to a host microprocessor,

i. means for receiving commands from said host micro-processor,

j. means for detecting the absence of data signals from said first data pathway,

k. means for detecting the absence of data signals from said second data pathway,

l. means for switching between said first data pathway and said second data pathway in the event of the detection of the absence of data in one of said data pathways.

9. A data network node according to claim 8 wherein said means (a) through (1) are implemented in an integrated circuit.

10. An apparatus for transmitting data asynchronously between data network nodes, comprising:

a. clock means for generating a clock interval signal, located at each node;

b. means for generating a data cell having a meaning dependent upon the time when said cell passes from a first voltage state to a second voltage state and returns to said first voltage state, said time determined by said clock means;

c. said data cell having the same meaning for a group of multiples of clock intervals and different meanings for different groups of multiples of clock intervals.

11. An apparatus according to claim 10, wherein said data cell is interpreted as having the same meaning for n-1, n, or n+1 4 clock interval signals, wherein n is an integer multiple of 3.

12. An apparatus according to claim 11, wherein said data cell is interpreted as having a value of zero when n=6, a value of one when n=3, and said data cell indicating the start of a message when n=9.

13. An apparatus according to claim 10 for transmitting data asynchronously between data network nodes, which further comprises:

elastic buffer means for receiving and elastically buffering data messages, comprised of said data cells.

14. A method for transmitting data asynchronously between data network nodes which comprises the steps of:

a. generating a clock interval signal at each node;

b. generating a data cell having a meaning dependent upon the time when said cell passes from a first voltage state to a second voltage state and returns to said first voltage state, said time determined by the number of clock interval signals;

c. said data cell having the same meaning for a group of multiples of clock intervals and different meanings for different groups of multiples of clock intervals.

15. A method according to claim 14, wherein said data cell is interpreted as having the same meaning for n-1, n, or n+1 clock interval signals, wherein n is an integer multiple of 3.

16. A method according to claim 15, wherein said data cell is interpreted as having a value of zero when n=6, a value of one when n=3, and said data cell indicating the start of a message when n=9.

17. A method according to claim 14 for transmitting data asynchronously between data network nodes which further comprises the steps of receiving data messages comprised of said data cells, and elastically buffering said received messages.

18. A self-healing data network comprising:

a. a plurality of nodes, each said node generating and receiving data signals asynchronously of said other nodes;

b. a primary data pathway connecting said nodes;

c. a secondary data pathway connecting said nodes;

d. each said node including;

(i) means for receiving signals from said data pathways,

(ii) means for decoding said signals,

(iii) means for storing said signals,

(iv) means for determining the time interval between receipt of messages from said primary data pathway,

(v) means for determining the time interval between receipt of messages from said secondary data pathway,

(vi) means for encoding data signals,

(vii) means for transmitting signals onto said data pathways,

(viii) means for switching from transmitting signals on said primary data pathway to said secondary data pathway when said interval between receipt of said messages on said primary data pathway exceeds a preset value.

19. In a data network node, an integrated circuit comprising:

a. first means for decoding first data signals from a first data pathway,

b. second means for decoding second data signals from a second data pathway,

c. first means for storing said first data signals independent of phase of said first data signals,

d. second means for storing said second data signals independent of phase of said second data signals,

e. means for recognizing messages in said data signals independent of clocking external to said integrated circuit,

f. means for switching between said first and second decoded data signals, said switching means providing an internal data stream,

g. means for communicating said internal data stream to a host processor external to said integrated circuit,

h. means for accepting commands from said hbst processor,

i. first means for detecting a fault in said first data pathway, independent of sources external to said integrated circuit,

j. second means for detecting a fault in said second data pathway, independent of sources external to said integrated circuit,

k. said means for switching responsive to said first and said second fault detection means,

l. first means for encoding said first data signals for said first data pathway,

m. second means for encoding said second data signals for said second data pathway.

20. An integrated circuit according to claim 19, wherein said means for detecting a fault in said first data pathway and said means for detecting a fault in said second data pathway are each comprised of timer means for determining the time interval between receipt of said respective first and second data signals.

21. An integrated circuit according to claim 19, wherein said first storage means comprises a two-stage first-in-first-out including a plurality of registers.

22. An integrated circuit according to claim 19, wherein said second storage means comprises a state machine-controlled three stage first-in-first out.

23. An integrated circuit according to claim 19, wherein each of said first and second means for detecting a fault comprises a five-stage linear feedback shift register.

24. An integrated circuit as in claim 19, wherein said first and said second means for decoding each comprises a finite state machine of 22 states.

25. An integrated circuit according to claim 19, wherein said first and said second means for encoding each comprises a finite state machine of 18 states.

26. An integrated circuit according to claim 19, wherein said means for communicating with said host processor comprises a plurality of buses connecting a plurality of registers.

27. In a data network, self-healing network switching apparatus comprising:

a. forward decoder means for decoding first data signals,

b. reverse decoder means for decoding second data signals,

c. forward timer means for determining the time interval between receipt of first data signals by said forward decoder means,

d. reverse timer means for determining the time interval between receipt of second data signals by said reverse decoder means,

e. inswitch means for switching between said first data and second data signals, said inswitch means communicating with said forward decoder means and said reverse decoder means,

f. elastic buffer means for asynchronous storage of said second data signals, said elastic buffer means communicating with said reverse decoder means,

g. reverse encoder means for encoding said second data signals, said reverse encoder means communicating with said elastic buffer means,

h. forward encoder means for encoding processed data signals,

i. outswitch means for switching between said processed and said second data signals,

j. heal control means for altering the positions of said inswitch means and said outswitch means, said heal control means communicating with said forward timer means and said reverse timer means,

k. said inswitch positioned to communicate solely with said forward decoder means and pass said first data signals therethrough if said forward timer means time interval does not exceed a preset value,

l. said outswitch positioned to communicate solely with said reverse decoder means and pass said second data signals therethrough if said forward timer means time interval does not exceed a preset value,

m. said inswitch positioned by said heal control means with said reverse decoder to communicate with said reverse decoder means, and said outswitch means positioned by said heal control means to communicate with ground, if said forward timer time interval exceeds a preset value,

n. said outswitch positioned by said heal control means to communicate with said forward encoder means, if said reverse timer time interval exceeds a preset value,

o. said inswitch positioned by said heal control means to communicate with said reverse decoder means and said outswitch means positioned by said heal control means to communicate with ground, if said forward timer time interval and said reverse timer time interval each exceed their respective preset values.