Reduce Latency on the local network
Latency is the time it takes from an input until viewing the result of the input. For example, the overall latency when using the Virtual Classroom can be experienced as the time it takes from clicking on a part until the menu is visible on screen.
There are two main contributions to latency for the Virtual Classroom
- Local Network Latency - The time that a message is being transferred from the user's computer to the local router, plus the time for the resulting message to be transferred back to the user's computer.
- Internet Latency - The round trip time the message and response spend on the Internet including the streaming server.
These are usually considered together, but it is useful to think of them as separate because the Local Network Latency is something that may be controllable.
Minimum Requirements
The following minimum system configuration specifications is expected for the device:
- Windows Desktop
- Windows Tablet (Surface Pro)
- Mac Desktop
- Broadband internet connection – 3 Mbps
- Latency to the hosted server to be less than 50ms
- Modern browser supporting HTML 5
Reduce Latency on the local network
To optimize the Local Network Latency, follow this suggestion:
- Use Wired Connection to the Internet
- If a Wired Connection is not available, favor a 5 GHz WiFi connection
- If 5 GHz is not available, use a lightly loaded 2.4 GHz WiFi connection
- A heavily loaded
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- WiFi connection is likely to produce an inconsistent undesirable experience
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To measure your Local Network Latency you can do the following. It will show the "ping time" to the local gateway (router) in milliseconds (ms).
In the example data below, the wired connection is generally less than 1ms.
A lightly loaded 5GHz WiFi was measured near 1ms with occasionally bumps
A heavily loaded 2.4GHz WiFi is showing unpredictable times of 5ms to 43ms in this example.
| Code Block |
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C:\> ipconfig |findstr "Default Gateway"
Default Gateway . . . . . . . . . : 192.168.42.1
C:\> ping 192.168.42.1
# Busy 2.4 GHz WiFi
Pinging 192.168.42.1 with 32 bytes of data:
Reply from 192.168.42.1: bytes=32 time=5ms TTL=64
Reply from 192.168.42.1: bytes=32 time=5ms TTL=64
Reply from 192.168.42.1: bytes=32 time=43ms TTL=64
Reply from 192.168.42.1: bytes=32 time=33ms TTL=64
# Lightly loaded 5 GHz WiFi
Pinging 192.168.42.1 with 32 bytes of data:
Reply from 192.168.42.1: bytes=32 time=1ms TTL=64
Reply from 192.168.42.1: bytes=32 time=1ms TTL=64
Reply from 192.168.42.1: bytes=32 time=12ms TTL=64
Reply from 192.168.42.1: bytes=32 time=1ms TTL=64
# Wired Connection
Pinging 192.168.42.1 with 32 bytes of data:
Reply from 192.168.42.1: bytes=32 time=1ms TTL=64
Reply from 192.168.42.1: bytes=32 time<1ms TTL=64
Reply from 192.168.42.1: bytes=32 time=1ms TTL=64
Reply from 192.168.42.1: bytes=32 time<1ms TTL=64
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Use Fast-Find
Moving the camera around the scene with the walk controls can become difficult if the network latency is too high. If you are using a high latency connection, a good way to improve movement is to use the Fast-Find feature.
This allows for automatically moving the camera/eye-point to specific locations around the content.
To toggle the option, click the top-right compass icon. Then select the area of interest. The camera will automatically move to that location.
Once in the general area, you can still use the walk and look controls for fine adjustments.
Use the full size of your screen
Poor - Viewing in a small browser
This will make it difficult to read text and interact with the controls.
Better
Expand the browser to use the full desktop using the Maximize button on the browser:
Best
For maximum quality, change the browser to full screen mode by using the "Enter fullscreen mode" at the top of the page.
This will cause the full width and height of your monitor to be used for displaying content
Web Browser Zoom
The web browser's zoom feature can significantly effect the visual quality of the streaming instance.
The default of 100% is normally ideal. However it is possible, and fairly common for Windows to have a desktop setting the text size adjustment like this:
For Google Chrome and other Chromium based browsers, like Microsoft Edge, the Virtual Classroom system includes and automatic adjustments to continue to work correctly.
However, Mozilla Firefox does not allow fixing this programmatically, so instead there is a warning system in place that lets the student know if they should increase or decrease the zoom factor for the ideal visual quality.
On the lesson selection screen the zoom level can be adjusted with CTRL+Mousewheel.
When the session has started, it may be necessary to use the Firefox setting menu zoom controls
When the correct zoom level has been achieved, the warning will disappear.
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