| Description of the subscription mechanism |  |
| When an exchange link between the target run and source batch is defined and activated, a subscription is automatically created by ERP LN and stored at the source site. An exchange of data is only possible if an active exchange link is available at the target site and the subscription is available at the source site. A subscribe message is sent to the source site when an exchange link is activated at the target site. The source checks and stores the subscription to make sure that it is correct and complete. From that moment the target site will be notified when the batch at the source site has run. An unsubscribe message is sent to the source site when a exchange link is deactivated at the target site. The status of the link is set to inactive at both sites, and the batch and table relation that would have been imported are deleted. The subscription will also be removed at the source site. A subscription destroyed message is sent to the target site when an source batch, or source exchange scheme is deleted at the source site. The subscriptions are also deleted. The exchange link to the source batch will be deactivated and receives the status inactive at the source and target sites. Note An exchange link can only be deleted if it has the status inactive at both sites. The subscription will be deleted if the exchange link is deactivated. Related topics Introduction to the Exchange module Introduction to multisite control To use exchange links |