International Business Machines Corporation

Harold A Himwich

Lap Thiet Huynh

Robert Andrew Vrabel

John E McGinn

Thomas P McSweeney

David Barrett Bryant

Loretta S Wolhar

Joseph R Mason

Mark A Cossack

Dennis J Frett

A method and apparatus for interconnecting multiple data processing networks, each data processing network including: multiple network nodes having routing and functional capability within a data processing network; and, multiple endpoint nodes, each including only local address capability. Each network node may be connected to multiple endpoint nodes and other network nodes; however, connection is only permitted to network nodes within the same data processing network. A border node is established for interconnection between two data processing networks. The border node includes a network node interface having routing and functional capability within a first data processing network and an endpoint node interface having local address capability. When interconnected between the first data processing network and a network node within a second data processing network, the border node emulates a network node within the first data processing network while appearing as an endpoint node within the second data processing network, permitting full connectivity between the two networks. The border node then maintains routing information for communication between the two data processing networks in two segments. A first segment details the route between the first data processing network and the border node while a second segment details the route between the border node and a node within the second data processing network.

Border node having routing and functional capability in a first network

A method and apparatus for allowing the higher layers of two nodes on a connection that uses an asynchronous link protocol to synchronize the exchange of messages so that, without knowledge of the lower data link protocols, the protocols at higher layers can complete when the data link protocols are also complete. The upper layer of a node sends messages for transmittal to another node to the lower layer of its node and receives messages from another node via the lower layer of its node. A first message, including an initiator flag is sent from the upper layer of the first node to the lower layer of the first node. In response, the lower layer transmits a second message including the initiator flag from the first message to the lower layer of the second node. The second message is transmitted as a command or a response in accordance with the send process state of the lower layer of the first node. If the upper layer of the first node subsequently detects a fourth message from the lower layer of the first node (which corresponds to a third message from the second node) and if the initiator flag is ON in the fourth message, the primary or secondary status of the first node is determined. If the first node is primary, the first message is resent to the lower layer of the first node until a message is received having the initiator flag set to OFF. The initiator flag is set to ON in all subsequent messages to the lower layer of the first node related to the first message. If the first node is secondary, the fourth message is discarded and the initiator flag in all subsequent messages to the lower layer of the first node related to the first message are set to OFF.

Synchronizing asynchronous protocol interactions between peer layers in

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Raleigh, NC, United States of America

Harold A Himwich