Doubt about message server

Hello ,

Today I have gone through SAP document and stuck at defination of message serevr

"Message Server (MS) handles communication between the distributed dispatchers within the AS ABAP, thereby enabling scalability of several

parallel application servers. The message server is configured only one per SAP system"

So As above statement tell MS is used between communication between diffrent dispatcher .

Suppose if I have only one instce (central instance ) so in this case what is job of message server.?

Because there is only one dispather so message server not requird here?

Please clarify this.

Do not post any lik or thread .I have searched in scn but didnt find suitable answer

BR

Atul