XenCenter is the central Windows-based multi-server management application (client) for XenServer hosts (including the open source version).
It is different to other management apps (e.g. SCVMM or vCenter) which typically have a management server/management client architecture where the management server holds centralized configuration information (typically in a 3rd party DB). Unlike these management consoles, XenCenter distributes management data across XenServer servers (hosts) in a resource pool to ensure there is no single point of management failure. If a management server (host) should fail, any other server in the pool can take over the management role. XenCenter is essentially only the client.
License administration is done using a separate web interface.