Method and apparatus for replicating information

Abstract

The present invention provides the ability to use an existing store-and-forward massaging network such as an electronic mail system to replicate data between computer sites. The replication provided by the present invention can be useful with software applications, such as workgroup applications, to replicate data located on multiple sites. Workgroup replication data is sent to other sites via electronic mail (“e-mail”) messages. The present invention provides reliability features to handle errors in electronic mail transmissions. For example, the present invention provides the ability to reassemble objects at a replication site such that an object and all of its dependencies exist prior to the object's use at the site. Messages referred to as “ACK” messages are used to communicate a site's state and to provide other control information. Each site maintains latency information to determine transmission failures.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to information sharing and replication via a store-and-forward massaging network. [0003] 2. Background Art [0004] In a business environment, computer users need to be able to communicate regarding aspects of the business. For example, a group of users may need to discuss a strategic planning document that is being prepared by the group. One member of the group may prepare a draft and send it to the other members. After reviewing the draft, one or more of the recipients may generate a reply. The reply may be, for example, a message regarding the document's contents, or a new document that contains modifications to the original document. The reply may be sent to the some or all of the group's members. [0005] The group interaction described above is facilitated using software that is referred to as workgroup software. A “workgroup” is a number of people who are associated on the basis of the prod...

AI Technical Summary

Benefits of technology

[0012] The invention enables remote users to participate in forums across network and geographic boundaries copying, workgroup information at multiple sites via an electronic store-and-forward messaging network. Using a store-and-forward messaging network, there is no need for immediate transmission of a message to a remote site. Thus, the replication provided by the present invention can be done without real-time connections between replication sites. Site databases do not need to be directly connected to perform replication. Site databases may be indirectly connected, for example, via e-mail. Since there is no need for direct connection between databases, there is no need to develop a “calling schedule” between site databases. Further, there is no need to provide dedicated communications hardware, telephone lines, or other infrastructure beyond that which is currently being used for e-mail.

[0030] The present invention implements techniques for controlling the flow of messages in the e-mail systems. An e-mail system has a finite capacity to store “in-transit” messages. To reduce the burden on the e-mail system, the replication agents practice a flow control discipline that limits the number of messages concurrently “in-transit” between any two agents, in conjunction with the ACK messages.

[0031] The present invention implements techniques for handling errors that may occur in e-mail transmissions. The present invention uses various techniques to minimize the effects that an error in transmission may cause. For example, replication agents must acknowledge to one another that every replication e-mail message sent was received without error. If an e-mail message is not acknowledged, it is automatically retransmitted. Further, the expected time to receive an acknowledgment is maintained for different sized messages for each site. Thus, the replication agent is constantly learning about the typical performance of the e-mail network with respect to specific distinctions. Therefore, the replication agent does not mistake normal variations in performance with an error condition. Further, it does not have to be manually tuned to maintain proper transmission behavior even when some sites receive their mail in minutes while others may not receive theirs for days, in the normal course of operation.

Problems solved by technology

However, a workgroup may not be centrally located.

Further, it requires additional work to coordinate and administer the “calling” schedule between the replication sites.

Images