• NCDesk
  • NCDesk Home
  • Download
  • Versions
    • About Versions
    • Download Current Release
    • Release History
    • Autoupdate
    • Demonstration Apps
  • Installation Instructions
  • Autoupdate
  • Helpdesk
  • Error Codes
  • Bug Reporting
  • Sample Files
  • File Conversion Guide
  • Test Simulation
    • About the Test Simulation
    • Test Simulation Demo Movie
  • Features Release Schedule
    • NCDesk (Global)
    • Editor
    • Database
    • Spreadheet
    • Window Manager
    • Mail
    • Multimedia
  • Technical Notes
    • Technical Notes Home
    • Spell Check Dictionaries
    • System Architecture
    • Autoupdate
    • Bandwidth-Network Use
    • Bandwidth-Footprint
    • Host Network Analysis
    • Testing Server
    • Requirements
      • Requirements Overview
      • Proposed Network Requirements
      • Proposed Client Requirements
    • Special Considerations
  • Test Registration System
  • Required Technical Project Management Documents
• New Test
  • New 2004 Test Home
  • Background
  • Strand Percentages
  • Events Planned for 2007-2008 School Year
  • Alternative Assessment
  • Accommodations
    • Approved Accommodations
    • Computer Reads Test Aloud
    • JAWS
  • Official actions-recommendations
  • Research/Studies/Results
    • Fall 2003 Study
    • Fall 2004 Trial
    • Spring 2005 Field Test
  • Goals
  • FAQ
    • All FAQs
    • Test Design
    • Accommodations/Special Needs
    • Test Simulation
  • Irregularity Reporting
  • Presentations
  • Guides & Manuals
    • Test Simulation Demo Movie
    • Administration Information Feasibility Study (Fall 2004)
    • Field Test Administration Manual (Spring 2005)
    • Administrative Information for Alternate (Spring 2005)
    • Test Administration Manual (September 2005)
  • Physical Test Environment
  • Test Security
  • Related Links
• New 2004 SCS
  • NCDPI Computer/Technology Skills SCS
• Other Tests Links
  • NCDPI Computer Skills Test Web Page
  • 1998 Curriculum Test (Archived Information)
    • 1998 Curriculum Test Handbook Website
    • 1998 Curriculum Test Handbook PDF
    • 1998 Curriculum Test Performance Sample Items And Files
  • 1992 Curriculum Test (Archived Site)

NCDesk

Technical Notes - Bandwidth Footprint Analysis

Results of analysis conducted averaging all forms of the spring 2005 field test on July 20 & 21, 2005

Almost as much data is transferred to the server as received from the server. Averaging out the data transmitted over 90 minutes, results in a data rate of .27 Kbps, sent upstream. Since most ISPs bias traffic flow against traffic going upstream, this should be the rate we are most concerned about. This is a very small data rate. Overall, the test requires transmition of a minimal amount of data.

The graph below shows that traffic tends to burst up to 10,000 Bytes/10 secs, or 8 Kbps, when bandwidth is freely available in the network. Bursts half that size are more common. The largest packets are those containing encrypted application data.

To get an idea how many users may take the test at once, given no other applications traffic on the network, assume the baseline is the 56K modem. While the paragraph above implies that seven users should be able to take the test at once on a 56K modem, in practice this is an unreasonable expectation. This is due to the fact that computers generate overhead traffic, and ISP's tend to overbook bandwidth. From practical experience, only one or two users may take the test over a 56K modem.

Please note that keeping to the minimum limits above will yield very good performance in general. As you start to approach the upper limit, performance will degrade, such that the test will be slow at the upper limits. Also, if other applications run at the same time as the test on the network, performance will be negatively impacted.

This file was modified on Wednesday, August 29, 2007; at 1:36:41 PM