Importance

Loading Importance Indicators...

Abstract

A system and method are provided for ensuring delivery of a communication from one computer system or node to another. A first node includes an object handler, such as an ORB (Object Request Broker), that receives object references from higher-level services operating on the first node, wherein the referenced object resides on a second node. The first node's object handler generates a message to an object handler on the second node and attempts to send the message to the second node through a transport module. The message is assigned a unique identifier, such as a sequence number. If the first object handler receives an uncertain status concerning the message (e.g., other than a certain success or failure), it issues a query to the second node to determine if the message was received. If the query is received by the second object handler before the message itself is received, the message is considered lost or rescinded by the first node. The first node stores the identifier so that it will not be re-assigned to another message and the message is then re-sent with a different identifier. The second object handler notes the identifier and status of the rescinded message and will discard any message having that identifier that is received. The second node includes two or more data structures to track the status of communications sent from the first node. The first node, in addition to a collection of identifiers of lost messages, may also record the status of communications it attempts to send and may also note the identifiers of messages that could not be transmitted (e.g., because of communication link errors).

Loading the Abstract Image...

First Claim