DOCUMENT:Q190436  22-APR-1999  [exchange]
TITLE   :XADM: How the Location of Public Folders Affects Clients
PRODUCT :Microsoft Exchange
PROD/VER:WINDOWS:5.0,5.5
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Exchange Server, versions 5.0, 5.5 
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SUMMARY
=======

This article discusses the process by which Exchange clients access public
folders when the location of these folders changes. The location can change if
an Exchange Server computer that is down for maintenance contains public folders
that are replicated to other Exchange Server computers. The location also can
change if a public folder is moved to another server by replicating it and then
deleting it from the original server.

MORE INFORMATION
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Two latencies are involved when the location of a public folder changes:

1. Directory replication latency to replicate this change to the other public
   folder servers in the location. If the servers are in the same site, this is
   typically 15 minutes at most.

2. Information store latency on the public folder servers to update their local
   cache of location information (called a sorted replica list) from their
   respective directories. This is done once every hour by default.

   On average, it takes about 40 minutes before the other servers are updated
   with the location change. After this happens, any client trying to open a
   public folder is given the sorted replica list (the list of locations where a
   public folder is available) according to the new location information.

   When a client logs on to Exchange and opens a public folder, it gets the fully
   sorted replica list for that public folder from its public folder hierarchy
   server and tries to connect to the replicas in approximately the order of the
   list. The client does not save a cache of replica servers for public folders.
   It gets this information from its hierarchy server each time a folder is
   opened.

   The client does have a cache of servers that it "knows" are down (when it
   fails to connect). The client tries to avoid these servers as much as
   possible while trying to connect to servers for content. Approximately every
   hour, the client attempts to poll these downed servers to see if they are
   back up.

   This means that if the server in your location is down, the client avoids it
   and goes to another location automatically without your having to change the
   location (after trying just once to open a folder on that downed server).

   The client switches back to the local server (the one in your location) if it
   becomes available while the client is running. This may affect what is seen
   in the client. The replicas of the public folder the client is using may not
   be identical, due to replication latency. So, if the client has a document
   open in the public folder and closes it before it switches to the local
   server, the changes may not be there when it is re- opened, or the document
   may not appear in the folder at all, depending on the situation. This is due
   to replication latency.

Additional query words: pf

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Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbZNotKeyword2
Version           : WINDOWS:5.0,5.5
Issue type        : kbinfo

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