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EP0416943A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method for controlling failover between redundant network interface modules

Assignee: Honeywell Inc
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Filing: 1990-09-07
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Granted: —
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Expires: 2010-09-07
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Abstract

Abstract A method by which redundant network interface modules (NIM)s interconnecting the communication buses of two local area networks communicate with one another at predetermined time intervals over the communication buses of both networks. One of the redundant pair of NIMs is designated as the primary and the other as the secondary. Contents of the information communicated between the NIMs over the communication bus of the first network includes the status of the transmitting NIMs ability to communicate with the second network and the information communicated between the NIMs over the communication bus of the second network includes the status of the transmitting NIM's ability to communicate with the first network. Based on the information exchanged, the failure of the NIMs to communicate as scheduled, and the internal status of each NIM as understood by that NIM, the NIM decide when failover from the primary NIM to the secondary NIM occurs.

Inventors

  • 👤 W Russell Massey, Jr.
  • 👤 Paul F. Mclaughlin
  • 👤 Renee Drobish

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 21:23
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2002; G06F11/2005; G06F11/2007; H; H04; H04L; H04L69/00; H04L69/40

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 189 words
Claim 1. The method by which redundant network modules (NIM)s interconnecting the communication buses of a first and a second local area network communicate with one another over the communication buses of the two networks, the first NIM being designated as the primary and the second NIM being designated as the secondary, the secondary NIM taking over the function of the primary NIM on the occurrence of certain predetermined conditions; comprising the steps of: the first and second NIMs communicating with each other at predetermined time intervals over the communication buses of both networks, each communication between the NIMs over the communication bus of the first network including the status of the second network as perceived by the NIM transmitting the message and each communication between the NIMs over the communication bus of the second network including the status of the first network as perceived by the NIM transmitting the message; the primary NIM failing over to the secondary NIM when the primary NIM determines that it is unable to communicate with the first network and the secondary NIM determines that is able to communicate with the first network.
Claim 2
Dependent Claim 30 words
Claim 2. The method of Claim 1 further comprising the step of the secondary NIM terminating its operation if the secondary NIM is unable to communicate with the first network.
Claim 3
Dependent Claim 51 words
Claim 3. The method of Claim 2 in which each communication between the NIMs includes current operating status of the NIM originating such a communication, and further comprising the step of the secondary NIM terminating its operation if the secondary NIM detects it has suffered a hardware or a software failure.
Claim 4
Dependent Claim 35 words
Claim 4. The method of Claim 3 further comprising the step of the primary NIM failing over to the secondary NIM if the primary NIM detects it has suffered a hardware or a software failure.
Claim 5
Dependent Claim 36 words
Claim 5. The method of Claim 4 in which the primary NIM fails over to the secondary NIM without communicating the fact that it has suffered a hardware or a software failure to the secondary NIM.
Claim 6
Dependent Claim 16 words
Claim 6. The method of Claim 5 in which the predetermined time intervals are one second.
Claim 7
Dependent Claim 19 words
Claim 7. The method of Claim 6 in which the first local area network is a token passing network.
Claim 8
Dependent Claim 19 words
Claim 8. The method of Claim 7 in which the second local area network is a token passing network.
Claim 9
Dependent Claim 549 words
Claim 9. In a process control system including an universal control network (UCN) and a local control network (LCN), each being a local area network (LAN) with each network including a plurality of modules, the modules of each network communicating with one another over a communication bus, a pair of network interface modules (NIM)s, one of said NIMs being designated as a primary and the other NIM being designated as a secondary, each of the NIMs being connected between the communication buses of the UCN and the LCN and functioning to provide communication and data translation between the UCN and the LCN, the primary NIM providing such function unless replaced by the secondary NIM, and the secondary NIM being available to provide this function instead of the primary NIM upon the occurrence of predetermined conditions; comprising the steps of: 1, the secondary NIM transmitting to the primary NIM at least once during every first period of time over the UCN's communication bus a status message, the secondary NIM's status message including the current operating status of the secondary NIM and the status of the LCN as determined by the the secondary NIM; 2, the primary NIM transmitting to the secondary NIM at least once during every first period of time over the UCN communication bus a status message, the primary NIM's status message including the current operating status of the primary NIM and the status of the LCN as determined by the the primary NIM; 3, the primary NIM transmitting to the secondary NIM at least once during every first period of time over the LCN communication bus a status message, the primary NIM's status message including current operating status of the primary NIM, of the UCN as determined by the primary NIM, and updating data with which the secondary NIM updates the secondary NIM's data base so that the data base of the secondary NIM substantially matches the data base of the primary NIM; 4, the secondary NIM transmitting to the primary NIM upon receiving a predetermined number of messages from the primary NIM in step 3 containing updating data or during every first period of time, which ever first occurs, over the LCN communication bus a status message, the secondary NIM's status message including the current operating status of the secondary NIM and the current operating status of the UCN as determined by the the secondary NIM; 5, the primary NIM failing over to the secondary NIM if the primary NIM if it is unable to communicate with the LCN, and the secondary NIM is able to communicate with the LCN and status messages containing such data are received by both NIMs; 6, the secondary NIM terminating its operations if it determines that it is unable to communicate with the LCN; 7, the primary NIM terminating operation of the secondary NIM if the secondary NIM is unable to communicate with one of the LANs; 8, the primary NIM terminating communications with the secondary NIM if the secondary NIM crashes; and 9, the secondary NIM taking over the function of the primary NIM if the primary NIM crashes, if the primary NIM is commanded to shut down by a command from a universal control station module of the first network, or if the primary NIM is powered down;
Claim 10
Dependent Claim 17 words
Claim 10. The method of Claim 9 in which the first period of time is one second.
Claim 11
Dependent Claim 18 words
Claim 11. The method of Claim 10 in which the universal control network is a token passing network.
Claim 12
Dependent Claim 18 words
Claim 12. The method of Claim 11 in which the local control network is a token passing network.

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