Saveetha,
Both ESAP and ISAP webMethods adapters are designed to connect their corresponding runtime systems to SAP. The ESAP connects the webMethods Enterprise system and the other adapter the IS system.
The enterprise system is event based and therefore works well for point-to-point integrations but really shines on 1-to-many integrations.
The ESAP adapters are designed to run on multiple parallel instances on the same host, while the IS adapter/server is designed for a single host enviroment.
The ESAP ALE in/out adapters are multithreaded, just as the ISAP adapter is.
The ESAP adapters run the native RFC/JCO libraries on the adapter process. So, in case of a crash of the SAP native libraries, the over all system is not affected because even if the adapter crashes nothing get lost.
The ISAP adapters load the native libraries on the same process that the IS uses. If the native libraries crash, this brings down the entire IS server.
The ESAP ALE client adapter includes some features not available in the ISAP adapters: generate IDOC files, append to multiple files at the same time(using multiple adapter instances), and allow for the usage of the “inbound_idoc_process” truely asynchronous IDOC execution even for a 4.x SAP systems.
The ISAP adapters provide some basic implementation of ALE monitoring, which the ESAP doesn’t have, but it can be configured and implemented manually fairly easily.
The ESAP adapters use the JCO 2.0.10 version, and handle I18N issues within the adapter. The ISAP uses later versions of the JCO libraries, and the myltibyte sypport is delegated in the sap libraries instead of the adapter.
The ESAP adapters are designed for memory efficiency and speed regardless of the size of the document.
The ISAP adapter uses XML nativelly, and runs on an Integration Server instance. Therefore has higher memory and CPU requirements as it is bound to the overall performance of the IS server itself.
Their configuration is conceptually very similar even though they use different tools and UI.
The future WmSAP adapter which will run nativelly on top of the new IS ADK6, will look very similar to the ESAP adapters from a configuration perspective, in terms of services and notifications.
hope this helps
vasilis
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