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Network Impact of Express Software Manager 6.x
Technical Note 1569
Last Reviewed 23-Sep-2002

Applies To
Express Software Manager version 6.0 and higher

Summary
This technical note lists the Express Software Manager (ESM) 6.x system requirements, describes the expected administrative and network impact of running ESM 6.x, and provides suggestions for minimizing the impact on your network.

System Requirements
Express Metrix recommends the following minimum system requirements for running Express Software Manager:

System Administrator Machine (to run Express Administrative Console and Express Reports Console):
Note: If you will be using the local installation of MSDE to store your library data for reporting, also see the SQL Server requirements.

  • Windows XP, Windows 2000, Windows NT 4.0 with service pack 5, Microsoft Terminal Services (Windows 2000 or greater, with or without MetaFrame)

    Note: You must have Administrator privileges on your machine to install and run Express Administrative Console and Express Reports Console.

  • Internet Explorer 5 or greater, standard install (DHTML component required)

  • 300 MHz or faster processor

  • 128 MB RAM minimum; 256 MB RAM strongly recommended

  • At least 250 MB free disk space

  • Minimum monitor resolution: 800 x 600 (no VGA support)

Network File Server (for the Application Library):
  • 200 MHz server class processor minimum; 333 MHz or faster recommended

  • 256 MB RAM minimum; 384 MB RAM or higher recommended

  • 500 MB hard disk space per library. Growth varies, but 600K per client (metering or inventory) is often required.

  • A network protocol such as Microsoft Networking or Novell NetWare

  • A server with an application library should not be used as a print mail server

  • If the application library is located on a Windows XP, 2000, or NT workstation (as opposed to a server), a maximum of 10 client machines will be able to connect to the library

  • On Windows NT or Windows 2000 Servers, OpLock should be disabled. For more information, see Technical Note 1316.

MSDE Machine (for the SQL Server database):
  • All hardware requirements of the system administrator machine, plus,

  • Windows XP, Windows 2000, or Windows NT 4.0 with service pack 5, or Windows Terminal Services (Windows 2000 or greater, with or without MetaFrame)

  • Internet Explorer 5 or greater, standard install (DHTML component required)

  • A network protocol such as Microsoft Networking or Novell NetWare

  • Allocated free space for the SQL Server database should allow enough space for a minimum of 1 MB per machine in the library. If you are gathering .dll files (in addition to the default .exe and .com files), and have metering enabled, requirements may be up to 2 MB per machine

User Workstation (to run Express Client)
  • Windows XP, Windows 2000, Windows NT version 3.51 or 4.0, Windows 98, or Windows 95, WinFrame 1.7, Microsoft Terminal Server

    Note: If users are running Windows XP, Windows 2000, or Windows NT 4.0 workstations without administrative rights, the Express Client Install Manager service will need to be configured, or an administrator must log in and install the Express client manually on each client workstation.

  • Minimum hard disk space (for 32-bit Windows Client): 800K, 600K Windows Memory (pageable memory)

  • Microsoft Networking or Novell NetWare

  • Minimum monitor resolution: 640 x 480 (supports VGA)

Network Impact
Express Software Manager uses standard Windows I/O API calls to transmit data to the network file server. Packet size, network performance, and protocols vary depending on the networking environment.

The Express client generates network traffic during these activities:

  • Installation

  • Metering applications

  • Inventorying workstations

Installation
Depending on the operating system, each workstation that runs Exinst.exe to install the Express client will generate approximately 1 MB of network traffic during installation. Copying files from the Clients folder of the library to the local workstation creates network traffic.

Metering Applications
A typical workstation that is metering to a library but not auto-adding applications or tracking crash detection will produce about 4 MB of network traffic over an eight-hour period

The Express metering client generates network traffic when

  • a user logs on to a metering workstation

  • a user logs off from a workstation

  • an application is launched

  • an application is closed

  • the Applib.lib file has been modified by an administrator

  • Crash Detection is enabled and an application is checked (the heartbeat)

Logging On
When a user enters a login name and password, some network traffic is incurred to validate to the machine that contains the library, and some traffic is generated by the metering client's initial startup procedure. The following files are read at logon:

  • Applib.ini

  • A00004s7.use

  • Express.log

  • Applib.key

  • Applib.mch

  • Applib.lgp

  • Applib.lib

An average size library requires between 500K and 1500K (0.5 to 1.5 MB) of network traffic during the startup process for a workstation. The amount varies depending on the amount of information retrieved from the files listed above. On larger networks where hundreds of users log into their machines at the same time, file contention problems may also cause an increase in network traffic (up to 500 bytes per machine).

A user logging on for the first time after the client is installed to the workstation will also cause an increase in network traffic. When the client is not previously installed, the traffic will increase to a maximum of 850K. Once the Express client is installed on the workstation and Exinst.exe is in the login script, the client generates only about 150K of traffic when run.

Logging Off
When a user shuts down the machine or logs off from a workstation, some network traffic will occur. Depending on the number of applications in use when the shutdown command is received, this traffic can vary greatly. The logoff procedure includes writing to the operation's system log file and the A00004s7.use file. Depending upon the file size, this network traffic can vary from 50K to 100K.

Launching an Application
The amount of network traffic that is required to meter an application varies, depending on the following factors:

  • Whether Maintain current usage is enabled for an application

  • Whether the application is concurrently licensed

  • How many users are currently using the application if Maintain current usage is enabled

  • Whether the application was auto-added

When an application runs for the first time on the workstation, two files, Applib.cli and Applib.unk, are downloaded from the server to the workstation.

Two following files are then created in the library, the .use file for the application, which is 500 to 900 bytes, and the .log file for the application, which is 5 to 10K.

Note: When the Auto-Added feature is enabled, a new application requires approximately 325 packets to be launched. When it is disabled, only 16 packets are required to launch a new application.

Effects of the Licensing and Current Usage Settings when launching an application
The following chart shows the network traffic generated in different scenarios when an application is launched.

Licensing
Maintain Current Usage
Number of packets
Traffic per user
Concurrent
Enabled
24
4K
Non-Concurrent
Enabled
28
4K
Non-Concurrent
Disabled
10
1.2K

Note: When a current usage application is launched, it must read the .use file for the application, which results in additional packets.

Closing an Application
The amount of network traffic required to close an application depends on the following factors:

  • Whether the application was auto-added

  • Whether Maintain current usage is enabled for an application

  • Whether the application is concurrently licensed

  • How many users are currently using the application if Maintain current usage is on

Closing Auto-Added Applications
When an application that was auto-added is closed, the Applib.cli, the .USE and .LOG files for the application are modified. This generates approximately 15K of network traffic per user.

Effects of the Licensing and Current Usage Settings when closing an application
The following chart shows the network traffic generated by applications with different licensing and current usage settings.

Licensing
Maintain Current Usage
Number of packets
Traffic per user
Concurrent
Enabled
22
6K
Non-Concurrent
Enabled
24
8K
Non-Concurrent
Disabled
12
5.5K

Modifying the Applib.lib File
When a system administrator modifies the Applib.lib file by configuring auto-added files or by adding, removing or modifying applications or suites, the Applib.lib file is changed. Once the Applib.lib file has been modified, at the next launch, the metering client will automatically read the new Applib.lib file. The file size may range from 50K to a few megabytes.

Checking an Application (with Crash Detection Enabled)
Crash detection opens the A*.use file for every running application (other than the operating system). This process of checking each application is called the heartbeat. Enabling crash detection results in approximately 12 packets per application plus 20 frames of additional overhead per heartbeat. One user running one application will generate approximately 3K of network traffic per heartbeat.

Inventorying Workstations
The inventory client's network usage varies depending on the inventory settings in Express Administrative Console and the number of files on the workstation. Increasing the number of directories, time limit, number of files to scan, or percentage of disk will increase the traffic generated by the initial high impact inventory scan.

Inventorying a typical workstation with 250 folders and 2500 files yields the following results:

  • A 100-percent high-impact scan lasts about two and one-half minutes and produces approximately 80 to 100K of network traffic.

  • A 500-file high-impact scan lasts about one and one-half minutes, and produce between 25 and 30K of network traffic.

  • A low-impact scan of one machine takes about 30 minutes and produces about 5 MB of network traffic, or 165K per minute.

Minimizing Network Impact
The following suggestions help minimize the network or server impact of ESM:

  • Routinely configure and/or remove files from the Auto-Added folder.

  • Routinely remove unnecessary applications from the library.

  • Remove Exinst32.exe from the login script.

  • Modify the Applib.lib file at a time when few users are modifying applications, or copy the library locally, make the appropriate changes, and copy it back.

  • Limit the size of each library to a maximum of 800 inventoried computers.

  • Limit the number of clients to a maximum of 800 per database (if using MSDE).

  • Run inventory less frequently.

  • In a large local area network or a network with limited bandwidth, limit the number of computers scanned with login scripts to 50 per day per library.

  • Use the Library properties Inventory tab entries to limit inventory activity or optional command line switches to specify a high-impact scan to limit the scan time for each computer. See the online help for details. (See the index entry for Switches|Inventory client.)

  • Remove the client from the login script after all computers have been scanned. This will remove a very small amount of network traffic that is generated when the client checks the Wrqexp.id file to see if 30 days have elapsed since the last scan.

  • Disable the auto-add feature.

  • Disable crash detection or increase the time intervals.

  • If metering, increase the Check application rate in the Metering tab in Express Administrative Console.

  • Monitor file access at the file server for unanticipated locking or caching failures.

Related Technical Notes
1304 Network Impact of Express Software Manager 4.x though 5.x
1316 Express Software Manager and Windows 2000/NT Server File Locking
1560 Understanding the Inventory Process in Express Software Manager 6.x
9989 Express Software Manager 6.x Technical Notes