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.

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.

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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