Distributed timing control for a distributed digital communication system

Claim 3

The method of claim 1 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan said TPN information it receives, (2) detecting when the received TPN information associated with said preferred clock signal changes on successive scans, and (3) switching the timing control of each node that detects a change from said preferred clock signal to a signal from a local oscillator internal to said last named node upon the detection of said change.

Claim 4

The method of claim 2 in combination with the additional steps of: (1) operating said last named node to continue its repeated scanning of said received TPN information, (2) comparing the results of successive scans, (3) determining when said received TPN information remains unchanged for a predetermined interval of time, and (4) analyzing said received TPN information after the expiration of said interval to select as a preferred clock signal for said node the signal that has encountered the least number of intermediate nodes in traveling from said master node to said receiving node.

Claim 5

The method of claim 1 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan said TPN information it receives, (2) operating one of said other nodes as a backup master node, (3) operating said backup master node to detect when said received TPN information associated with said preferred clock signal changes from a prior value to a predetermined value, (4) switching the timing control of said backup master node from said preferred received clock signal to a signal from a local oscillator internal to said backup master node upon the detection of said change to said predetermined value, and (5) transmitting a clock signal containing TPN information over directly connected ones of said links from said backup master node to control the timing of all nodes of said system other than said master node.

Claim 8

The method of claim 5 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan the TPNs it receives, (2) detecting a change when the received TPNs associated with said preferred clock signal changes on successive scans, and (3) switching the timing control of said node that receives said changed TPNs from said preferred clock signal to a signal from a local oscillator internal to said last named node upon the detection of said change.

Claim 9

The method of claim 6 in combination with the additional steps of: (1) operating said last named node to continue its repeated scanning of said received TPNs, (2) comparing the results of successive scans, (3) determining when said received TPNs remain unchanged for a predetermined interval of time, and (4) analyzing said received TPN information after the expiration of said interval to select as a preferred clock signal for said node the clock signal received over the link on which a TPN having a prescribed relationship to the TPNs of other links is received.

Claim 10

The method of claim 5 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan said received TPNs, (2) operating one of said other nodes as a backup master node, (3) operating said backup master node to detect when said received TPN associated with said preferred clock signal changes from a prior value to a predetermined value, and (4) switching the timing control of said backup master node form said preferred received clock signal to a signal from a local oscillator internal to said backup master node upon the detection of said change to said predetermined value, and (5) transmitting a clock signal contain a TPN over directly connected ones of said links from said backup master node to control the timing of all nodes of said system other than said master node.

Claim 15

The method of claim 10 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan the TPNs it receives, (2) detecting a change when the received TPN associated with said preferred clock signal changes on successive scans, and (3) switching the timing control of said node that detects a changed TPN from said preferred clock signal to a signal from a local oscillator internal to said last named node upon the detection of said change.

Claim 16

The method of claim 11 in combination with the additional steps of: (1) operating said last named node to continue its repeated scanning of said received TPNs, (2) comparing the results of successive scans, (3) determining when said received TPNs remain unchanged for a predetermined interval of time, and (4) analyzing said received TPNs after said interval to select as a preferred clock signal for said node the clock signal received over the link on which a TPN having a prescribed relationship to the TPNs of other links is received.

Claim 17

The method of claim 10 in combination with the additional steps of: (1) operating each node, other than said master node, to repeatedly scan said received TPNs, (2) operating one of said other nodes as a backup master node, (3) operating said backup master node to detect when said received TPN associated with said preferred clock signal changes from a prior value to a predetermined value, and (4) switching the timing control of said backup master node from said preferred received clock signal to a signal from a local oscillator internal to said backup master node upon the detection of said change to said predetermined value, and (5) transmitting a clock signal containing a TPN over directly connected ones of said links from said backup master node to control the timing of all nodes of said system other than said master node.

Claim 18

Facilities for controlling the timing of each node in a multinode system whose nodes are interconnected by links and wherein a clock source in one of said nodes provides a reference clock signal source for controlling the timing of all other nodes in said system, said facilities comprising: means for operating one of said nodes as a master node to control the timing of all nodes of said system, means for transmitting a clock signal between each pair of said nodes directly interconnected by any one of said links, means for including timing priority number (TPN) information in the clock signal transmitted between each pair of directly connected nodes with said information representing the priority of said clock signal, means for operating each clock signal receiving node, other than said master node, to analyze the TPN information it receives on all links to which it is connected to identify a preferred clock signal, means for modifying the TPN from the directly connected node which transmitted said preferred clock signal, means for transporting the modified TPN to all nodes directly connected to said clock signal receiving node, and means for operating each clock signal receiving node to select said preferred clock signal as a reference timing source for said receiving node.

Claim 19

Facilities for controlling the timing of each node in a multinode system whose nodes are interconnected by links and wherein a clock source in one of said nodes provides a reference clock signal source for controlling the timing of all other nodes in said system, said facilities comprising: means for operating one of said nodes as a master node to control the timing of all nodes of said system, means for transmitting a clock signal between each pair of said nodes directly interconnected by any one of said links, means for including timing priority number (TPN) information in the clock signal transmitted between each pair of directly connected nodes with said information representing the priority of said clock signal, means for operating each clock signal receiving node, other than said master node, to analyze the TPN information it receives on all links to which it is connected to identify a preferred clock signal, means for modifying the TPN from the directly connected node which transmitted said preferred clock signal, means for transporting the modified TPN to all nodes directly connected to said clock signal receiving node, and means for operating each clock signal receiving node to select said preferred clock signal as a reference timing source for said receiving node.

Claim 20

The facilities of claim 14 in combination with: means for operating each node, other than said master node, to repeatedly scan said TPN information it receives, means for detecting when the received TPN information associated with said preferred clock signal changes on successive scans, and means for switching the timing control of said node that receives said changed TPN information from said preferred clock signal to a signal from a local oscillator internal to said last named node upon the detection of said change.

Claim 21

The facilities of claim 15 in combination with: means for operating said last named node to continue its repeated scanning of said received TPN information, means for comparing the results of successive scans, means for determining when said received TPN information remains unchanged for a predetermined interval of time, and means for analyzing said received TPN information after the expiration of said interval to select as a preferred clock signal for said node the signal that has encountered the least number of intermediate nodes in traveling from said master node to said receiving node.

Claim 22

The facilities of claim 14 in combination with: means for operating each node, other than said master node, to repeatedly scan said TPN information it receives, means for operating one of said other nodes as a backup master node, means for operating said backup master node to detect when said received TPN information associated with said preferred clock signal changes from a prior value to a predetermined value, means for switching the timing control of said backup master node from said preferred received clock signal to a signal from a local oscillator internal to said backup master node upon the detection of said change to said predetermined value, and means for transmitting a clock signal containing TPN information over directly connected ones of said links from said backup master node to control the timing of all nodes of said system other than said master node.

Claim 23

Facilities for controlling the timing of each node in a multinode system whose nodes are interconnected by links and wherein a clock source in one of said nodes provides a reference clock signal source for all other nodes in said system, said facilities comprising: means for operating one of said nodes as a master node to control the timing of all nodes of said system, means for including a timing priority number (TPN) in the clock signal transmitted from said master node over a direct link to at least another one of said nodes, means for operating each node, other than master node, so that it alters a TPN it receives over a directly connected link in a prescribed manner to form a new TPN, means for further operating each node, other than said master node, so that each said node sends a clock signal together with its altered TPN to all nodes to which it is directly connected by a link, means for operating each node, other than said master node, to identify one of the TPNs received as a preferred TPN based upon a prescribed relationship of said received TPNs, and means for controlling the timing of each said node, other than said master node, by the clock signal received over he link over which said preferred TPN is received by said node.

Claim 24

Facilities for controlling the timing of each node in a multinode system whose nodes are interconnected by links and wherein a clock source in one of said nodes provides a reference clock signal source for all other nodes in said system, said facilities comprising: means for operating one of said nodes as a master node to control the timing of all nodes of said system, means for including a timing priority number (TPN) in the clock signal transmitted from said master node over a direct link to at least another one of said nodes, means for operating each node, other than master node, so that it alters a TPN it receives over a directly connected link in a prescribed manner to form a new TPN, means for further operating each node, other than said master node, so that each said node sends a clock signal together with its altered TPN to all nodes to which it is directly connected by a link, means for operating each node, other than said master node, to identify one of the TPNs received as a preferred TPN based upon a prescribed relationship of said received TPNs, and means for controlling the timing of each said node, other than said master node, by the clock signal received over he link over which said preferred TPN is received by said node.

Claim 25

The facilities of claim 18 in combination with: means for operating each node, other than said master node, to repeatedly scan said TPNs it receives, means for detecting a change when the received TPN associated with said preferred clock signal changes on successive scans, and means for switching the timing control of said node that receives a changed TPN from said preferred clock signal to a signal from a local oscillator internal to said node upon the detection of said change.

Claim 26

The facilities of claim 19 in combination with: means for operating said last named node to continue its repeated scanning of said received TPNs, means for comparing the results of successive scans, means for determining when said received TPNs remain unchanged for a predetermined interval of time, and means for analyzing said received TPNs to select as a preferred clock signal for said node the clock signal received over the link on which a TPN having a prescribed relationship to the TPNs of other links is received.

Claim 27

The facilities of claim 18 in combination with: means for operating each node, other than said master node, to repeatedly scan said received TPNs, means for operating one of said other nodes as a backup master node, means for operating said backup master node to repeatedly scan said received TPNs to detect when said received TPN associated with said preferred clock signal changes from a prior value to a predetermined value, and means for switching the timing control of said backup master node from said preferred received clock signal to a signal from a local oscillator internal to said backup master node upon the detection of said change to said predetermined value, and means for transmitting a clock signal containing a TPN over directly connected ones of said links from said backup master node to control the timing of all nodes of said system other than said master node.

Claim 28

Facilities for controlling the timing of each node in a multinode system wherein said nodes are connected by links and wherein a clock source in a master one of said nodes provides a reference clock signal for all other nodes in said system, said facilities comprising: links for directly interconnecting each of said nodes to one or more other of said nodes, means for transmitting a clock signal between each of said nodes directly interconnected by any one of said links, means for activating one of said nodes to operate as a master node by providing a reference clock signal for controlling the timing of said system, means for including a timing priority number (TPN) of n in the clock signal sent from said master node to all of said nodes directly connected to said master node by any one of said links, means for operating each node directly connected by a link to said master node and receiving said TPN of n to alter n by m to form a TPN of n+m characterizing each said directly connected receiving node, means for further operating each node having a TPN of n+m to include said TPN of n+m in the clock signal transmitted to each one of said nodes to which said node having a TPN of n+m is directly connected by any one of said links, means for operating all others of said nodes, other than said master node, that receives a TPN of n+m so that each of sad other node alters a TPN it receives by m and transmits its altered TPN with a clock signal to each node to which it is directly interconnected by any one of said links, means for operating each node that receives more than a single TPN, other than said master node, to select one of said received TPNs as a preferred received TPN, and means for controlling the timing of each node, other than said master node, from clock signals transmitted over the link that applies the preferred TPN to said controlled node.

Claim 29

Facilities for controlling the timing of each node in a multinode system wherein said nodes are connected by links and wherein a clock source in a master one of said nodes provides a reference clock signal for all other nodes in said system, said facilities comprising: links for directly interconnecting each of said nodes to one or more other of said nodes, means for transmitting a clock signal between each of said nodes directly interconnected by any one of said links, means for activating one of said nodes to operate as a master node by providing a reference clock signal for controlling the timing of said system, means for including a timing priority number (TPN) of n in the clock signal sent from said master node to all of said nodes directly connected to said master node by any one of said links, means for operating each node directly connected by a link to said master node and receiving said TPN of n to alter n by m to form a TPN of n+m characterizing each said directly connected receiving node, means for further operating each node having a TPN of n+m to include said TPN of n+m in the clock signal transmitted to each one of said nodes to which said node having a TPN of n+m is directly connected by any one of said links, means for operating all others of said nodes, other than said master node, that receives a TPN of n+m so that each of sad other node alters a TPN it receives by m and transmits its altered TPN with a clock signal to each node to which it is directly interconnected by any one of said links, means for operating each node that receives more than a single TPN, other than said master node, to select one of said received TPNs as a preferred received TPN, and means for controlling the timing of each node, other than said master node, from clock signals transmitted over the link that applies the preferred TPN to said controlled node.

Claim 30

Facilities for controlling the timing of a clock signal receiving node in a multinode system whose nodes are interconnected by links and wherein a clock source in a master one of said nodes provides a reference clock signal source for controlling the timing of all other nodes in said system, said facilities comprising: means for receiving timing priority number (TPN) information together with a clock signal on each different link connected to said signal receiving node with said TPN information representing the number of intermediate nodes each received clock signal has encountered in traveling from said master node to said signal receiving node, means for operating said signal receiving node to analyze the TPN information it receives on all links to which it is connected to identify as a preferred clock signal the clock signal that has encountered the least number of intermediate nodes in traveling from said master node to reach said signal receiving node, means for selecting said preferred clock signal as a reference timing source of said signal receiving node, means for modifying the TPN received from the link from which said preferred clock signal was received, and means for transmitting the modified TPN on all links to which said signal receiving node is connected.

Claim 31

Facilities for controlling the timing of a clock signal receiving node in a multinode system whose nodes are interconnected by links and wherein a clock source in a master one of said nodes provides a reference clock signal source for controlling the timing of all other nodes in said system, said facilities comprising: means for receiving timing priority number (TPN) information together with a clock signal on each different link connected to said signal receiving node with said TPN information representing the number of intermediate nodes each received clock signal has encountered in traveling from said master node to said signal receiving node, means for operating said signal receiving node to analyze the TPN information it receives on all links to which it is connected to identify as a preferred clock signal the clock signal that has encountered the least number of intermediate nodes in traveling from said master node to reach said signal receiving node, means for selecting said preferred clock signal as a reference timing source of said signal receiving node, means for modifying the TPN received from the link from which said preferred clock signal was received, and means for transmitting the modified TPN on all links to which said signal receiving node is connected.

Claim 32

Facilities for controlling the timing of a clock signal receiving node in a multinode system whose nodes are interconnected by links said facilities comprising: means for receiving timing priority number (TPN) information together with a clock signal on each different link connected to said signal receiving node with said TPN information representing the relative priority of each received clock signal, means for operating said signal receiving node to analyze the TPN information it receives on all links to which it is connected to identify a preferred clock signal having a preferred priority, means for selecting said preferred clock signal as a reference timing source for said signal receiving node, means for modifying the TPN received from the link from which said preferred clock signal was received, and means for transmitting the modified TPN on all links to which said signal receiving node is connected.

Claim 33

Facilities for controlling the timing of a clock signal receiving node in a multinode system whose nodes are interconnected by links said facilities comprising: means for receiving timing priority number (TPN) information together with a clock signal on each different link connected to said signal receiving node with said TPN information representing the relative priority of each received clock signal, means for operating said signal receiving node to analyze the TPN information it receives on all links to which it is connected to identify a preferred clock signal having a preferred priority, means for selecting said preferred clock signal as a reference timing source for said signal receiving node, means for modifying the TPN received from the link from which said preferred clock signal was received, and means for transmitting the modified TPN on all links to which said signal receiving node is connected.

Claim 36

The method of claim 25 in combination with the additional steps of: (1) detecting when the received TPN information associated with said preferred clock signal changes, and (2) switching the timing control of each node that detects a change from said preferred clock signal to another clock signal upon the detection of said change.