you can install SMBR either on one Exchange server or on a dedicated server.
If you are using it with the snapcenter integration you need to deploy also the windows plugin and the other thing you need os Outlook (32 bit)
SMBR needs to run on server on which Microsoft Outlook is running, and it uses native Microsoft Messaging Application Program Interface (MAPI) protocol to communicate with the Microsoft Exchange Server that is running on a separate machine.
Keep in mind that SMBR passes a query to identify the host name for Exchange, hence the backup snapshots will only load on the active server. So the mount operation will be perfomed on the server where the active database runs.