Asynchronous hub

• US 7,630,390 B2
• Filed: 11/19/2004
• Issued: 12/08/2009
• Est. Priority Date: 11/19/2003
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Zumsteg, Philip J., Driscoll, Kevin R., Hall, Brendan
• Primary Examiner(s): Rao; Seema S
• Assistant Examiner(s): DUONG, CHRISTINE T
• Application Number:
  US10/993,911
• Publication Number:
  US 20050135404A1
• Time in Patent Office: 1,845 Days
• Field of Search: 370/229, 370/230, 370/235, 370/240, 370/314, 370/321, 370/336, 370/347, 370/348, 370/395.21, 370/395.4, 370/395.42, 370/425, 370/442, 370/443, 370/444, 370/447, 370/458, 370/461, 370/462
• US Class Current: 370/425
• CPC Class Codes: H04L 12/43 with synchronous transmission, e.g. time division multiplex [TDM], slotted rings
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04L 2012/6459 Multiplexing, e.g. TDMA, CDMA
• CPC Class Codes: H04L 2012/6464 Priority
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS

Abstract

A method for arbitrating access to a time slot in a time division multiple access network in an asynchronous hub with a bus guardian is provided. The method including receiving signals from competing nodes claiming access to the same time slot at the bus guardian of the asynchronous hub, selecting one of the nodes based on a priority scheme, and relaying a message from the selected node and blocking the message from the non-selected node.

Claims

1. A method for arbitrating access to a time slot in a time division multiple access network, the method comprising:

receiving signals at each of at least two asynchronous hubs from competing nodes claiming access to the same time slot;

selecting, at each of the at least two asynchronous hubs, one of the nodes based on a priority scheme, wherein each of the at least two asynchronous hubs implements a different, complementary priority scheme such that the node with a higher port number is selected at one of the at least two asynchronous hubs and the node with a lower port number is selected at another of the at least two asynchronous hubs;

relaying a message from the selected node having the higher port number and blocking the message from the non-selected node having the lower port number at one of the at least two asynchronous hubs; and

relaying a message from the selected node having the lower port number and blocking the message from the non-selected node having the higher port number at another of the at least two asynchronous hubs.

2. The method of claim 1, and further including inserting a period of silence when each of the at least two asynchronous hubs begins relaying a message from the non-selected node prior to receiving the signal from the selected node.

3. A method for relaying messages at least two hubs from a plurality of nodes, the method comprising:

receiving a subsequent signal at each of the at least two hubs from a node during relaying of a message from another node, wherein each of the at least two hubs implements a different, complementary priority scheme;

interrupting relaying of the message at one of the at least two hubs when the node sending the subsequent signal has a higher priority based on a first priority scheme, wherein, based on the first priority scheme, the node sending the subsequent signal has a higher priority when the node sending the subsequent signal has a higher port number than the node sending the message; and

interrupting relaying of the message at another of the at least two hubs when the node sending the subsequent signal has a higher priority based on a second priority scheme, wherein, based on the second priority scheme, the node sending the subsequent signal has a higher priority when the node sending the subsequent signal has a lower port number than the node sending the message.

4. The method of claim 3, and further including continuing relaying the message when the node sending the subsequent signal has a lower priority.

5. The method of claim 3, wherein receiving a signal comprises receiving a clear to send signal.

6. The method of claim 3, wherein interrupting relaying the message comprises granting access to the node with higher priority.

7. The method of claim 3, wherein interrupting relaying the message includes inserting a silence period before relaying the message from the higher priority node.

8. A network, comprising:

at least two asynchronous hubs;

a plurality of nodes coupled to each of the at least two hubs in a star configuration;

wherein the at least two hubs and the plurality of nodes communicate using time slots in a time-triggered protocol; and

wherein each of the at least two asynchronous hubs arbitrates between two nodes of the plurality of nodes that claim the same time slot by granting access to a higher priority one of the two competing nodes of the plurality of nodes, wherein each of the at least two hubs implements a different, complementary priority scheme such that one of the at least two asynchronous hubs grants access to the node with a higher port number and another of the at least two asynchronous hubs grants access to the node with a lower port number.

9. A method for relaying messages at least two asynchronous hubs of a time division multiple access network, the network including a plurality of nodes coupled to each of the at least two hubs, the method comprising:

receiving a signal at each of the at least two hubs from a node claiming access to a time slot;

determining at each of the at least two hubs whether another node has already claimed access to the time slot;

when another node has already claimed access to the time slot, granting access to the time slot to the node with a highest priority and relaying a message from the node with the highest priority at each of the at least two hubs based on a different, complementary priority scheme in each of the at least two hubs;

wherein relaying a message from the node with the highest priority at one of the at least two hubs comprises relaying a message from the node with a higher port number; and

wherein relaying a message from the node with the highest priority at another of the at least two hubs comprises relaying a message from the node with a lower port number.

10. A method of relaying messages at least two asynchronous hubs in a time division multiple access network, the method comprising:

receiving a signal at each of the at least two hubs from a first node of the network claiming a next time slot;

beginning to relay a message from the first node;

receiving a signal from a second node of the network indicating that the second node is assigned the time slot claimed by the first node;

determining at each of the at least two hubs whether the second node has a higher priority than the first node based on a different, complementary priority scheme in each of the at least two hubs such that the node with a higher port number has a higher priority at one of the at least two hubs and the node with a lower port number has a higher priority at another of the at least two hubs;

when the second node has a higher port number, relaying the message from the second node at one of the at least two hubs; and

when the second node has a lower port number, relaying the message from the second node at another of the at least two hubs.

11. The method of claim 10, and further comprising inserting a period of silence before relaying the message from the second node when the second node has a higher priority.

12. The method of claim 10, wherein receiving a signal comprises receiving a clear to send signal.

13. A method for controlling relaying of messages from a plurality of nodes by at least two asynchronous hubs in a network, the method comprising:

at each of the plurality of nodes, determining a time slot assigned for that node to transmit a message from that node to another of the plurality of nodes through the at least two hubs;

activating a signal at each of the plurality of nodes that has identified a next time slot as the assigned time slot for that node to transmit a message from that node to the other nodes of the plurality of nodes through the at least two hubs; and

when each of the at least two hubs receives a signal from two of the plurality of nodes making a claim to the same time slot, selectively relaying, at each of the at least two hubs, one of the two competing messages from the two nodes to the other nodes of the plurality of nodes in the network based on a different, complementary priority scheme in each of the at least two hubs;

wherein selectively relaying at least one of the two competing messages comprises;

passing one of the messages to the other nodes on a first channel based on a first priority scheme; and

passing the other of the messages to the other nodes on a second channel based on a second priority scheme;

wherein passing one of the messages based on the first priority scheme comprises selecting the message associated with the node with a higher port number at one of the at least two hubs and passing the other of the messages based on the second priority scheme comprises selecting the message associated with the node with a lower port number at another of the at least two hubs.

14. A method for arbitrating access to a dual medium, the method comprising:

receiving signals at each of at least two hubs from competing nodes claiming access to at least two media;

selecting, at each of the at least two hubs, one of the nodes based on a priority scheme, wherein each of the at least two hubs implements a different, complementary priority scheme such that the node with a higher port number is selected at one of the at least two hubs and the node with a lower port number is selected at another of the at least two hubs; and

relaying a message from the selected node having the higher port number at one of the at least two hubs; and

relaying a message from the selected node having the lower port number at another of the at least two hubs.

15. The method of claim 14, further comprising:

receiving a subsequent signal at each of the at least two hubs from another node claiming access to the at least two media;

determining at each of the at least two hubs whether the other node has a higher priority than the selected node based on a different, complementary priority scheme in each of the at least two hubs;

when the other node has a higher priority, interrupting the relayed message of the selected node and relaying a message from the other node; and

when the selected node has a higher priority, continuing to relay the message from the selected node.

16. A network, comprising:

at least two asynchronous hubs;

a plurality of nodes, each of the plurality of nodes coupled to each of the at least two asynchronous hubs via a medium; and

wherein each of the at least two asynchronous hubs arbitrates between two nodes of the plurality of nodes that claim access to at least two media by granting access to a higher priority one of the two competing nodes of the plurality of nodes, wherein each of the at least two asynchronous hubs implements a different, complementary priority scheme such that one of the at least two hubs grants access to the node with a higher port number and another of the at least two hubs grants access to the node with a lower port number.