By default, Windows 7 only displays a link for the network map on the Network and Sharing Center if you're connected to a Private network, defined the first time you connected.
However, you can make the mapping feature work on Domain and Public networks as well using the Local Group Policy Editor:
- Open gpedit.msc.
- Navigate to Computer Configuration\Administrative Templates\Network\Link-Layer Topology Discovery.
- Double-click the Turn On Mapper I/O (LLTDIO) Driver policy, select Enabled, and then select Allow Operation While In Domain. Then click Next Setting.
- Double-click the Turn On Responder (RSPNDR) Driver policy, select Enabled, and then select Allow Operation While In Domain. Then click Next Setting.
- Click OK.