Troubleshooting TCP Throughput

Good presentation of TCP Throughput troubleshooting:
PDF:  http://packetbomb.com/understanding-throughput-and-tcp-windows
Video with example:
https://www.youtube.com/watch?v=qFWjugyKyrE

Thanks to kory@packetbomb.com

Packet-Level: Am I looking at a trace from client side or server side?

Look at 3 way handshake (SYN, SYN/ACK, ACK.)
  - Client side trace will have delay between SYN & SYN/ACK
  - Server side trace will have delay between SYN/ACK & ACK.

Duh, this is obvious!  Some might say.  But I find it insightful as TCP analysis is just a "hobby" -- I do it so rarely in my work that I learn and re-learn each time I need to slog through a trace file.

powershell query remote sharepoint

Example of query to a sharepoint list on a remote machine.

############################################################################################
# Create $list of server names - in Service Catalog where status equals selection
#

[array]$list = $null
$uri = "http://portal/apps/systemscatalog/_vti_bin/lists.asmx?WSDL"
$listName = "Server Catalog" 

# Create xml query - get the whole list
$xmlDoc = new-object System.Xml.XmlDocument
$query = $xmlDoc.CreateElement("Query")
$vfxml = "" +
 "" +
 "" +
 "" +
 ""
$viewFields = $xmlDoc.CreateElement("ViewFields")
$queryOptions = $xmlDoc.CreateElement("QueryOptions")
$query.set_InnerXml("FieldRef Name='Full Name'") 
$rowLimit = "3000"
$serverlist = $null 
$service = $null  
try{
    $service = New-WebServiceProxy -Uri $uri  -Namespace SpWs  -UseDefaultCredential
}
catch{ 
    Write-Error $_ -ErrorAction:'SilentlyContinue' 
}
if($service -ne $null){
    try{        
        $serverlist = $service.GetListItems($listName, "", $query, $viewFields, $rowLimit, $queryOptions, $null)
    }
    catch{ 
        Write-Error $_  -ErrorAction:'SilentlyContinue'
    }
}
$output = $serverlist.data.row


if ( -not $output) {
 clear-host
 "ERROR:  No output from sharepoint"
 "ERROR:  No output from sharepoint" | out-file $logfile -append
 exit
 }

[string]$status = $null
foreach ($item in $output) {
 [string]$status = $item.ows_DeploymentStatus
 $Server = $item.ows_Title
 $dmz = $item.ows_IsDMZServer
 if ($dmz -eq $null) { $dmz = 0 }
 if($status -eq $selection) { 
   if ($filterDMZ -and (-not $dmz)) {
  if ($Server) { $list = $list + $Server} #skip a null value
   }#end if
   else {
       if ($Server) { $list = $list + $Server} #skip a null value
       }
 }#end if
 [string]$status = $null 
} #end foreach

#

$list = $list | sort-object

if ( -not $list) { 
    "ERROR:  No server list to check"
    "ERROR:  No server list to check" | out-file $logfile -append
    exit
    }

TCP Congestion Avoidance

Thanks samarai_apoc.
http://www.slideshare.net/samarai_apoc/congestion-control-in-tcp

tcp analysis: TCP Slow Start Algorithm

Great explanation of the TCP slow start algorithm:
tcp-slow-start
Thanks Jeremy of PacketLife.net

tcp analysis: time sequence graph (tcptrace)

Great troubleshooting tip video using WireShark:
Time Sequence Graph - Info (PDF)
Time Sequence Graph - Video
Thanks Kary@packetbomb.com