Click “Master Server” Menu to access to the main interface (see the following figure). In this interface, the administrator may view the ID and name of the upper node, and make modification and deletion and other operations on such node. In the below figure, it can be seen that there is a record in the list of master server. That indicates that the server is a sub-server. As a master server only, a server will only have record in sub-server list and will not have any record in master server list