Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
1998-11-10
2001-10-23
Ray, Gopal C. (Department: 2181)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C714S056000, C710S120000, C370S216000
Reexamination Certificate
active
06308282
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to network data communications. In particular, the present invention relates to apparatus and methods providing fault tolerance of networks and network interface cards, wherein middleware facilitates failure detection, and switching from an active channel to a stand-by channel upon detection of a failure on the active channel.
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawings hereto: Copyright © 1998, Honeywell, Inc., All Rights Reserved.
BACKGROUND OF THE INVENTION
Computer networks have become widely popular throughout business and industry. They may be used to link multiple computers within one location or across multiple sites.
The network provides a communication channel for the transmission of data, or traffic, from one computer to another. Network uses are boundless and may include simple data or file transfers, remote audio or video, multimedia conferencing, industrial process control and more.
Perhaps the most popular network protocol is Ethernet, a local area network (LAN) specification for high-speed terminal to computer communications or computer to computer file transfers. The Ethernet communication protocol permits and accommodates data transfers across a bus, typically a twisted pair or coaxial cable. Other media for data bus exist, such as fiber optic bus or wireless bus as just two examples. For convenience, the generic term bus will be used, regardless of media type.
A typical LAN will have a number of nodes connected to and in communication with the LAN. Each node will have a network interface card (NIC) providing the communication link to the physical LAN through a drop to the LAN. Alternatively, several nodes may be connected to a network hub, or switch, through their respective network interface cards. In addition, multiple LANs may be bridged together to create larger networks.
Nodes generally comply with the OSI model, i.e., the network model of the International Standards Organization. The OSI model divides network communications into seven functional layers. The layers are arranged in a logical hierarchy, with each layer providing communications to the layers immediately above and below. Each OSI layer is responsible for a different network service. The layers are 1) Physical, 2) Data Link, 3) Network, 4) Transport, 5) Session, 6) Presentation and 7) Application. The first three layers provide data transmission and routing. The Transport and Session layers provide the interface between user applications and the hardware. The last three layers manage the user application. Other network models are well known in the art.
While the Ethernet protocol provides recovery for message collision across the network, it is incapable, by itself, of recovering from failure of network components, such as the network interface cards, drops, hubs, switches, bridges or bus. Fault tolerance is thus often needed to assure continued node-to-node communications. One approach proposed by others is to design redundant systems relying on specialized hardware for failure detection and recovery. However, such solutions are proprietary and vendor-dependent, making them difficult and expensive to implement. These hardware-oriented systems may be justified in highly critical applications, but they may not be highly portable or expandable due to their specialized nature.
Accordingly, there exists a need for cost-effective apparatus and methods to provide fault tolerance that can be implemented on existing Ethernet networks using commercial-off-the-shelf (COTS) Ethernet hardware (network interface cards) and software (drivers and protocol). Such an open solution provides the benefits of low product cost, ease of use and maintenance, compliance with network standards and interoperability between networks.
SUMMARY OF THE INVENTION
A middleware approach provides network fault tolerance over conventional Ethernet networks. The networks have a plurality of nodes desiring to transmit packets of data. Nodes of the fault-tolerant network have more than one network connection, and include nodes having multiple connections to one network and nodes having single connections to multiple networks. A network fault-tolerance manager oversees detection of failures and manipulation of failure recovery. Failure recovery includes redirecting data transmission of a node from a channel indicating a failure to a stand-by channel. In one embodiment, failure recovery restricts data transmission, and thus receipt, to one active channel. In another embodiment, failure recovery allows receipt of valid data packets from any connected channel. In a further embodiment, the active channel and the stand-by channel share common resources.
The middleware comprises computer software residing above a network interface device and the device driver, yet below the system transport services and/or user applications. The invention provides network fault tolerance which does not require modification to existing COTS hardware and software that implement Ethernet. The middleware approach is transparent to applications using standard network and transport protocols, such as TCP/IP, UDP/IP and IP Multicast.
In one embodiment, a network node is simultaneously connected to more than one network of a multiple-network system. The node is provided with a software switch capable of selecting a channel on one of the networks. A network fault-tolerance manager performs detection of a failure on an active channel. The network fault-tolerance manager further provides failure recovery in manipulating the switch to select a stand-by channel. In a further embodiment, the node is connected to one active channel and one stand-by channel.
In a further embodiment, a network fault-tolerance manager performs detection and reporting of a failure on a stand-by channel, in addition to detection and recovery of a failure on an active channel.
In another embodiment, a node is simultaneously connected to more than one network of a multiple-network system. The node is provided with an NIC (network interface card) for each connected network. The node is further provided with an NIC switch capable of selecting one of the network interface cards. A network fault-tolerance manager provides distributed detection of a failure on an active channel. The network fault-tolerance manager further provides failure recovery in manipulating the NIC switch to select the network interface card connected to a stand-by channel. In a further embodiment, the node is connected to one active channel and one stand-by channel.
In a further embodiment, at least two nodes are each simultaneously connected to more than one network of a multiple-network system. Each node is provided with a network interface card for each connected network. Each node is further provided with an NIC switch capable of selecting one of the network interface cards. A network fault-tolerance manager provides distributed detection of a failure on an active channel. The network fault-tolerance manager further provides failure recovery in manipulating the NIC switch of each sending node to select the network interface card connected to a stand-by channel. Data packets from a sending node are passed to the stand-by channel. Valid data packets from the stand-by channel are passed up to higher layers by a receiving node. In this embodiment, all nodes using the active channel are swapped to one stand-by channel upon detection of a failure on the active channel. In a further embodiment, each node is connected to one active channel and one stand-by channel.
In a still further embodiment, at least two nodes are each simultaneously connected to more than one netw
Huang Jiandong
Li Ling
Song Sejun
Honeywell International , Inc.
Ray Gopal C.
Shudy, Jr. John G.
LandOfFree
Apparatus and methods for providing fault tolerance of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and methods for providing fault tolerance of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and methods for providing fault tolerance of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2574687