Multiplex communications – Network configuration determination
Reexamination Certificate
1996-08-23
2001-02-13
Nguyen, Chau (Department: 2739)
Multiplex communications
Network configuration determination
C370S401000, C370S475000
Reexamination Certificate
active
06188675
ABSTRACT:
TECHNICAL FIELD
The present invention relates in general to communication networks, and more particularly, to a system and method for self-identifying and configuring the interconnected nodes of a network having an unknown or partially unknown topology. The plurality of interconnected nodes of the network includes multiple switch nodes connected together by links.
BACKGROUND ART
The configuring of nodes in a communication switching network, such as employed by International Business Machines in their RS/6000 Workstation architecture, is typically performed statically, with each node preassigned an addressed before the switch network is utilized. However, such static configuring of network nodes is inherently inflexible and adds complexity to a network installation process.
Conventionally, the nodes of a network can also be configured by mapping the topology of the network through either the exchange of information on a separate network, or through the passive monitoring of traffic on the network. Clearly, the addition of a separate, second network to determine topology of a first network adds cost and complexity to a system. Further, passive monitoring of traffic on a network can require an unacceptably long delay before the network topology is known.
Fiber distributed data interface (FDDI) and token ring both use neighbor notification methods where nodes send packets that are only received by their neighboring nodes. This approach allows individual nodes to communicate only with their direct neighbors, but by monitoring traffic on the network, a remotely located managing node can discover the neighbors of all other nodes in the network. This method means waiting for all nodes of the ring to transmit to their neighbors, often requiring as long as thirty seconds to complete, which can comprise an unacceptable latency. Further, this method requires that the managing node be disposed within the ring itself.
As more computer systems incorporate interconnection or switching networks as a highbandwidth fault-tolerant means of connecting processors and input/output (I/O), a quick and inexpensive approach to identifying and configuring the nodes of the network becomes important. The use of such interconnection networks in personal computer (PC) systems places an even stronger requirement on the initialization approach; i.e., it should automatically recognize new devices and properly configure them, while still being quick and inexpensive. With personal computers moving to plug and play capabilities, it is only a matter of time before workstations must be able to self-identify their internal interconnection topology. The present invention addresses this need by providing an approach that allows network self-identification.
More particularly, an approach for configuring nodes is needed that can explore an interconnection network having unknown topology using the network itself. Further, an approach is desired which allows the searching of unknown portions of the network so that new devices can be discovered, along with a method for configuring nodes that allows multiple managing nodes to remotely initialize the network, without race conditions causing errors or conflicts. The present invention addresses each of these needs.
DISCLOSURE OF THE INVENTION
Briefly summarized, the invention comprises a system for use in identifying the topology of a network having a plurality of nodes. Each node includes a port for transfer of a packet to a next adjacent node in the network. The system includes an all-node address indicator and means for selectively employing the all-node address indicator. The all-node address indicator is designed for selective insertion in a field of the packet, wherein when inserted in the field of the packet, the all-node address indictor causes the packet to be received by the next adjacent node in the network notwithstanding that a node address of the next adjacent node in the network is unknown upon forwarding of the packet. The means for selectively employing the all-node address indicator comprises means for selectively inserting the indicator into the packet at each node of the network with a known node address having a next adjacent node in the network with an unknown node address.
In a more specific aspect, the invention comprises a system for use in identifying the topology of a network having a plurality of interconnected nodes. Each node includes a port for transfer of the packet to a next adjacent node in the network. The system includes an all-node address indicator for selective insertion in a field of the packet, wherein when inserted in the field, the all-node address indicator causes the packet to be received by the next adjacent node in the network. Each node has a port control register for each port which when set instructs the node to insert the allnode address indicator into the field of the packet before forwarding the packet to the next adjacent node in the network. Means are provided for remotely, selectively setting the port control registers associated with the ports of the plurality of interconnected nodes. The all-node address indicator causes the packet to be received by the next adjacent node in the network notwithstanding that the node address of the next adjacent node coupled to the particular port of the node is unknown when forwarding the packet.
In a further aspect, a self-identifying network is provided which includes a plurality of interconnected nodes, each node having a port for transfer of a packet to a next adjacent node in the network. An all-node address indicator is provided for selective insertion in a field of the packet, wherein when inserted in the field, the all-node address indicator causes the packet to be received by a next adjacent node in the network notwithstanding that the next adjacent node has an unknown node address. Automatic means selectively employs the all-node address indicator at each node of the network with a known node address having a next adjacent node with an unknown node address, to thereby identify the topology of the network.
In a still further aspect, the invention comprises a method for identifying topology of a network having a plurality of interconnected nodes, each node having a port for transfer of a packet to a next adjacent node in the network. A given node of the plurality of interconnected nodes has a known node address and is connected to a next adjacent node with an unknown node address. The method includes: sending a packet to the given node with known node address for output to the next adjacent node with unknown node address; upon receipt of the packet at the given node, providing in the packet an all-node address indicator, the all-node address indicator directing the packet to be received by any node of the plurality of interconnected nodes; and sending the packet with the all-node address indicator to the next adjacent node with unknown node address such that the packet is received at the next adjacent node.
To restate, this invention comprises a system and method for identifying and configuring the nodes of a network when an unknown or partially known topology is present. The invention employs a progressive identification of the network by allowing the interrogation of next adjacent network nodes beyond those previously identified. Specifically, network topology is progressively discovered through a process that proceeds by identifying the network node by node, where each additional new node is located at the other end of a link from a previously identified node. The approach presented herein allows self-identification of the network, while still being inexpensive to implement. Further, an approach is presented for configuring all nodes of the network so that node configurations can be managed from multiple managing nodes in the network simultaneously. Monitoring of a discovered topology is possible to identify additions, deletions or other changes to the network. Race conditions or conflicts between multiple managing nodes are avoided. The system/method can be employed with any
Casper Daniel Francis
Gregg Thomas Anthony
Nation George Wayne
Ocheltree Kenneth Blair
Perkins, Jr. Charles Bertram
Heslin & Rothenberg, P.C.
Hyun Soon-Dong
International Business Machines - Corporation
Nguyen Chau
LandOfFree
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