A. When a client accesses a link in a Dfs hierarchy, the client obtains a list of link targets sorted by site location (i.e., link targets in the client's local site are listed first). The client then attempts to access the first link target on the list and, if it's successful, uses that link target until one of the following things happens:
- The computer is restarted.
- The client cache is cleared.
- The Time To Live (TTL) on the referral expires.
If the client continues to access a link target, the TTL for the referral continues to be reset, which means the client never checks back with the Dfs server for an updated link target list.
Usually, if a client moves from one location to another, the user restarts the computer. Doing so causes the client to requery the Dfs server for the list of referrals to link targets. This list is reordered according to the client's new site location, thereby letting the client use a link target in its new site. However, if the user puts the client computer into hibernation instead of restarting it, the link-target list isn't updated. The client laptop continues to use its referral cache to access data, so the TTL never expires; thus, the client can never use a more local version of the data. It's important that mobile users shut down their laptops when they change locations so that Dfs can function correctly.
