Hi Shuai,
Yes, The application servers communicate with the presentation components, the database, and also with each other, using the message server.
Please find the below link for your reference which will help you to get more details
Application Servers - BC - ABAP Programming - SAP Library
2) If I want to use messager-server configure in sap logon, what I should do?
please follow the below link which will help to understand and configure logon load balancing group
https://help.sap.com/saphelp_nw70/helpdata/en/c4/3a644c505211d189550000e829fbbd/content.htm
In short:
Activities at SAP application
-Create a logon group - Tcode SMLG
-Enter the instance name and save
Activities at OS level
- Ensure that services file(C:\windows\system32\etc\drivers\services) hold this entry for SAP server e.g DEV
sapmsDEV 3601/tcp ## Here instance number for SAP system is 01
-Never forget to hit enter after this entry.
Activities at SAP GUI
- Select connection type "Group/Server selection"
- Maintain all required details SID, Message server IP/Hostname
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Br,
Best Friend
