VPN performance and QoS Packet Scheduler?

  • Thread starter Thread starter Per Salmi
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Per Salmi

Hi!

We have a Win2K server at the office enabling us to access the office
network through VPN.
However, tasks like browsing file systems on servers at the office when
connected to the VPN is awfully slow, it can take minutes to change folder.

But I noticed that if the QoS Packet Scheduler is installed for the LAN
connection in the computer at home it also shows up om the VPN connection
and the remote file system browsing is much faster!

Is this a known fact that QoS should be enabled when using VPN to increase
performance? Or is there another explanation?

Best regards,
Per Salmi
 
In its simplest form, QoS Techniques are used to control and prioritize
outgoing traffic from your PC. To explain that, imagine that you are logged
to the Internet, and you are browsing the Web (WWW Service), downloading a
file using the FTP Protocol (FTP), connecting remotely to a Telnet Server
(Telnet), sending e-mails (SMTP), playing Video & Audio files, and finally
logging remotely using RDC. As you can see, the Traffic leaving/Entering
your PC can fall under many other categories (Application Protocols). Each
of these categories has its own unique requirements to run smoothly. Take a
video and audio streaming for example, you will find that the requirements
of this application is to have a minimum delay and loss factor in regard to
the data traversing the Network (If you have delay, you may find the Audio
choppy sometimes, and the video will have freezes intervals within it). On
the other hand, delay does not affect FTP file transfers ( at the end of the
day, the file will arrive at its destination). Now how will be the situation
when both types of traffic will live on the same network? Imagine that data
packets of both types arrive at the connecting router, and that FTP packets
arrived, a little bit earlier. Here the router has to queue the A/V data
(Delay), until all the FTP packets are transmitted. This is called a best
effort transmission model (a model with no QoS applied), now, imagine that
the router will have a good behaviour of prioritizing the transmission of
data packets of A/V traffic over all other traffic types. The performance
for the A/V service in the last case will surely improve (this is QoS). So,
in your case, for the QoS Scheduler to have a positive effect on the RDC,
then you need to be running more than that service to notice the difference
between the two states (applying QoS or Not).
 
Ok, so you don't think the QoS thing was the cause of the speed improvement?
At the moment I didn't even use any other network applications than the
ordinary
Windows Explorer browsing a file system shared from the server.

Are there any known reasons that can cause extremely slow browsing of shared
file systems?
Specifically when the performance differs depending on what server I access.
When in the office all server appear to have about the same browsing
performance but at home, over VPN, some of them are extremely slow.

/Per Sami
 
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