A. By default, the new Link Layer Topology Discovery (LLTD) protocol that's responsible for discovering information about a network is disabled when a Vista machine is part of a domain. (It's only enabled when the network is designated as "Home" and not "Work" or "Public."). If you try to select the "View full map" from the Network and Sharing Center, a message will be displayed that says "Network mapping is disabled by default on domain networks. Your network administrator can use Group Policy to enable mapping."
To enable this functionality locally on a machine, start the Group Policy Editor (GPE--gpedit.msc) as Administrator and navigate to the Local Computer Policy, Computer Configuration, Administrative Templates, Network, Link-Layer Topology Discovery branch. Double-click "Turn on Mapper I/O (LLTDIO) driver" and set it to Enabled, and select the check boxes for "Allow operation while in domain" and "Prohibit operation while in public network," As the figure shows. Click Apply, then click OK and close the GPE.
The option "Turn on Responder (RSPNDR) driver" allows the machine to participate and return information to LLTP requests from other machines and again can be enabled for domain environments.
More information on the LLTD and other connectivity technologies can be found at http://www.microsoft.com/whdc/rally/default.mspx.