ping.send and timeout issues

[Stoobert]

OK, What I am trying is a very basic "Ping" but it seems to ignore the timeout value I set in the ping.send overload...

Imports System.Net
Imports System.Net.NetworkInformation
 
Dim ping As New Ping
Dim intTimeout As Integer = 200
Dim reply as PingReply = ping.Send("192.168.12.200", intTimeout)
Dim q As Integer = reply.RoundtripTime
Console.WriteLine(q & " " & intTimeout)
 
Select Case reply.Status
    Case IPStatus.TimedOut
        Console.WriteLine(reply.Status.ToString)
    Case IPStatus.Success
        Console.WriteLine("Success")
    Case Else
        Console.WriteLine(reply.Status.ToString)
End Select

That should be that if it takes longer than 200ms it is classed as a "Time Out" and returns 0 for the ping time, however it replies as a success when the ping time is greater than the timeout value.

Note: the cases are there with the code snipped as they are not relevant because it always passes into the "success" category.

Any ideas? I have tried using Async pings too, but they produce the same result...

Cheers,

Stu

[dbasnett]

that is what it does, and always has done. the command line ping does the same thing. if you dig around MSDN you will find the answer as to why (i used to have it, but can't seem to find it).

[dbasnett]

see Remarks here http://msdn.microsoft.com/en-us/library/ms144955.aspx

[Stoobert]

When specifying very small numbers for timeout, the Ping reply can be received even if timeout milliseconds have elapsed.

Any idea what constitues a "very small number" as 250ms doesn't seem all that small to me. Looks like I may have to use Async with my own implementation if it can't be as small as that...

[dbasnett]

yes, that is a small timeout, and so is 1. why is it important? i chased this once and just ended up frustrated.

[Stoobert]

There are probably better ways around it, but we have some sort of issue with users and DCs over client and site-to-site VPN connections whereby we get random and sporadic disconnects. I was hoping to be able to take the standard Microsoft ping client and increase the frequency to more than 1 per second. This then would be installed on a server in each site and started synchronously by adding a listening socket for a "go" command to try and get an overview of latency and the such over the VPN links.

[dbasnett]

another rough idea

Imports System.ComponentModel, System.Net.NetworkInformation, System.Threading
Public Class Form1
    Dim WithEvents pinger As New BackgroundWorker
    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        pinger.CancelAsync()
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        pinger.WorkerReportsProgress = True
        pinger.WorkerSupportsCancellation = True
        pinger.RunWorkerAsync()
    End Sub
    Dim tmo As Integer = 1000
    Dim sent, good, bad As Long
    Dim rtt As Double, avgRTT As Long, swRTT As Long
    Private Sub pinger_DoWork(ByVal sender As Object, _
                              ByVal e As System.ComponentModel.DoWorkEventArgs) _
                              Handles pinger.DoWork
        Dim aPing As New Ping, reply As PingReply, stpw As New Stopwatch
        rtt = 0
        Do
            stpw.Start()
            reply = aPing.Send("192.168.1.1", tmo)
            swRTT = stpw.ElapsedMilliseconds 'alternative time
            stpw.Stop()
            sent += 1
            Select Case reply.Status
                Case IPStatus.Success
                    rtt += reply.RoundtripTime
                    good += 1
                Case Else
                    bad += 1
            End Select
            avgRTT = CLng(rtt / sent)
            If swRTT < tmo Then Thread.Sleep(CInt(tmo - swRTT))
        Loop While Not pinger.CancellationPending
    End Sub
End Class