Controlling network speed for any process by powershell? - powershell

Question

I am using powershell to do folder sync. My question is that how does "Copy-Item" use the network bandwidth / speed ? Does it use all available bandwidth? or it is controlled by Windows automatically.
Because my sync process will be performed through vpn, so I would like to control the speed of sync to 500K, is that possible to do it in powershell Like this software does?
function Get-FileMD5 {
Param([string]$file)
$md5 = [System.Security.Cryptography.HashAlgorithm]::Create("MD5")
$IO = New-Object System.IO.FileStream($file, [System.IO.FileMode]::Open)
$StringBuilder = New-Object System.Text.StringBuilder
$md5.ComputeHash($IO) | % { [void] $StringBuilder.Append($_.ToString("x2")) }
$hash = $StringBuilder.ToString()
$IO.Dispose()
return $hash
}
#VARIABLES
$DebugPreference = "continue"
#parameters
$SRC_DIR = 'VPN POINT'
$DST_DIR = 'VPN POINT'
#SCRIPT MAIN
clear
$SourceFiles = GCI -Recurse $SRC_DIR | ? { $_.PSIsContainer -eq $false} #get the files in the source dir.
$SourceFiles | % { # loop through the source dir files
$src = $_.FullName #current source dir file
Write-Debug $src
$dest = $src -replace $SRC_DIR.Replace('\','\\'),$DST_DIR #current destination dir file
if (test-path $dest) { #if file exists in destination folder check MD5 hash
$srcMD5 = Get-FileMD5 -file $src
Write-Debug "Source file hash: $srcMD5"
$destMD5 = Get-FileMD5 -file $dest
Write-Debug "Destination file hash: $destMD5"
if ($srcMD5 -eq $destMD5) { #if the MD5 hashes match then the files are the same
Write-Debug "File hashes match. File already exists in destination folder and will be skipped."
$cpy = $false
}
else { #if the MD5 hashes are different then copy the file and overwrite the older version in the destination dir
$cpy = $true
Write-Debug "File hashes don't match. File will be copied to destination folder."
}
}
else { #if the file doesn't in the destination dir it will be copied.
Write-Debug "File doesn't exist in destination folder and will be copied."
$cpy = $true
}
Write-Debug "Copy is $cpy"
if ($cpy -eq $true) { #copy the file if file version is newer or if it doesn't exist in the destination dir.
Write-Debug "Copying $src to $dest"
if (!(test-path $dest)) {
New-Item -ItemType "File" -Path $dest -Force
}
Copy-Item -Path $src -Destination $dest -Force
}
}

Answer 1

There's a Network Emulator feature in Visual Studio 2010 (and probably newer). Maybe you can get that to work from PowerShell. Otherwise I think you'll have to resort to NetLimiter or one of the alternatives:
TMNetSim
Network Simulator
netem

Answer 2

Robocopy does have the ability though and you can wrap it in PowerShell via Invoke-Expression.