HiPath 4000 Manager resides on an external server, and is used to manage a single HiPath 4000 or a network of 4000s. In a network of 4000s, it allows the administrator to "see" and manipulate the entire network's database, rather than accessing each system's Assistant individually. One feature that only Manager can do: "move" a station from one 4000 system to another - and automatically revise the routing so that the station can be dialed from all sites at its new location.
Manager requires a license. The HiPath 4000 Manager is not something that you merely "get a copy of".
Typically Manager is not necessary TODAY if the customer has only one HiPath 4000. In the past it has provided at least one feature (SNMP) that pre-V4 HiPath 4000 systems could not provide - which is why you might see the Manager at some customer locations with only one 4000. Since V4, the 4000 can support SNMP internally.