SUMMARY
This article outlines some of the tuning considerations to think about when
you implement Microsoft Schedule+. You should have a general understanding
of Schedule+ server and clients to obtain value from this section.
NOTE: The following information is from the Microsoft Mail Resource Kit,
Chapter 4, pages 129-131.
The Schedule Distribution Process
Schedule distribution is the process by which an administrator can send
snapshots of user's appointment books to another postoffice so users on
that postoffice can view the data. These snapshots--schedule distribution
mail messages, actually--contain the following information:
- Free/busy bits for each user on the postoffice.
- Flags specifying which accounts on the postoffice are resources.
- A list of the assistants for those users on the postoffice who
have assistants.
This information is sent only if a change occurs. For example, if there are
150 users on a postoffice but only 10 users have modified their schedule
since the last schedule distribution message was sent, only 10 new sets of
free/busy bits are sent in the next schedule distribution message.
The schedule distribution information is kept in the CAL directory of the
receiving postoffice. On every postoffice, there is one postoffice file
(POF) for each postoffice that sends it schedule distribution messages.
Schedule distribution is configured through the Schedule+ administration
program. The actual work of distributing schedule information is done when
the schedule distribution program is run.
With schedule distribution, users can view free/busy information for users
on another postoffice without having network access or access privileges to
the other postoffice. Once the user has viewed the free/busy time of users
on other postoffices, they can send a meeting request.
Limitations
The network traffic caused by schedule distribution is predictable, as
explained below. Schedule distribution allows Schedule+ to quickly find out
if users on other postoffices have assistants or are resources. Schedule+
needs to know this information to decide where to send meeting requests.
Schedule distribution uses the mail system to route information across
different LANs. Schedule distribution can cause a large amount of
consistent network traffic.
This process does not allow users on one postoffice to see anything more
than free/busy time of users on other postoffices. Schedule distribution
alone cannot enable a user on one postoffice to view appointment details,
modify appointment books, or act as an assistant for a user on another
postoffice.
Additionally, schedule distribution alone does not let users on one
postoffice automatically book resources on another postoffice. The process
of schedule distribution requires the schedule distribution program to be
run, either manually or continuously, on a dedicated machine or with other
processes using the DISPATCH.EXE program.
Message size
The size of each schedule distribution message is determined by:
- the number of Schedule+ users on the postoffice
- the number of schedule changes the average user makes each day
- the frequency with which schedule distribution messages are sent
- the number of months of data sent by schedule distribution.
Each schedule distribution message contains the following data:
Information Size
Message header 100 bytes
Assistant/resource information
for each user whose free/busy
information has changed 25 bytes
One month of free/busy
information for one user 20 bytes
For example, if an administrator chooses to distribute 3 months of schedule
data and 10 users on the postoffice have changed their appointments since
the last schedule distribution, the schedule distribution message will be
100+{10x[25+(3x20)]}=950 bytes. Of course, these numbers will vary
depending on the frequency of schedule distribution, number of months of
data propagated, and the frequency of schedule activity per user on the
postoffice.
Each schedule distribution message is very small. On a large network,
however, these messages can really add up. On a mail network with 100
postoffices all participating in schedule distribution, for instance, each
postoffice could send up to 99 schedule distribution messages per "round"
of schedule distribution. If every postoffice sends to every other, 9,900
messages are sent during every round of schedule distribution.
Optimizing the Performance of a Schedule+ 1.0 Installation
This section outlines the tuning options available for a Schedule+ 1.0
installation.
Server:
Do not over-send free/busy information. If you do not need to have each
others free/busy information updated every 10 minutes, then do not set up
SchDist to send this information so often. A user's free/busy information
may not change very often, and an organization may need just an idea of
when a user might be free of busy. Find a reasonable interval for your
organization, recognizing that decreasing the interval to give users more
up-to-the-minute information increases the messages that must be processed.
Also, send free/busy information only where it makes sense. If users on two
postoffices do not schedule meetings with each other very often (or at
all), do not set up SchDist between them.
Do not run SchDist across time zones. Because Schedule+ does not work
across time zones, there is no need to run schedule distribution across
time zones. In fact, doing so will cause confusion for the users.
Use dynamic postoffice connections very sparingly. Dynamic postoffice
connection establishes network connections between postoffices. Therefore,
it may cause network traffic to increase, because every Schedule+ user
could connect to multiple postoffices. Limiting the number of dynamic
postoffice connections will help limit the amount of network traffic. A
common practice is to allow everyone to be able to dynamically connect to
the postoffice that contains the conference rooms and other resources, but
that is all.
When using dynamic postoffice connections, still run SchDist between the
two postoffices. Most users will not need to dynamically connect to other
postoffices to see detailed, up-to-the-second information on other
calendars. Free/busy information as recent as the last SchDist cycle is
usually enough. Running SchDist at least once a day will make the Schedule+
system run more efficiently by reducing network traffic.
Client:
When working remotely, work offline. Schedule+ performs slowly across dial-
up connections because of its infrastructure. Working offline keeps
Schedule+ from trying to update the user's calendar (CAL) file on the
postoffice. Then, when the user is back online, Schedule+ updates the
user's CAL file with the changes they made while working offline.
Change how often Schedule+ updates the user's CAL file. By changing the
CopyTime parameter in the SCHDPLUS.INI file, a user can control how often
(in minutes) that the online CAL file is copied to the local CAL file. The
default time is 15 minutes.