Learn how to a build a cloud-first strategyRegister Now


How much bandwidth do you get when running a PPTP VPN?

Posted on 2011-10-28
Medium Priority
Last Modified: 2013-08-29
SImple question.  How much bandwidth do you get when running a PPTP VPN?  Connecting a Windows XP computer to a Windows 2003 server.  No tweating of settings so far, so how much bandwidth will the person get? I suppose I may say, how much equivalent bandwidth do they get inf there's a chance everything's slowed down by encryption.  (Asking mainly because our VPNs seems very slow when people are downloaidng files.)
Question by:wibber1
  • 2
LVL 33

Expert Comment

ID: 37045259
IIRC, PPTP has 32 bits of overhead on any packet.  

So a 1500 MTU packet, lets say you are on PPPoE DSL makes it 1500-8=1492, then a PPTP makes it 1492-36 = 1456.

So basically you would lose about 2.5% of bandwidth to PPTP overhead.  


Author Comment

ID: 37114077
So does that mean that the VPN should have as much bandwidth as the connection minus 2.5%?
LVL 33

Accepted Solution

MikeKane earned 500 total points
ID: 37117806
More or less.   the MSS size of each possible packet is smaller so the tcp stream may need additional packets to complete.      The bandwidth is close, however the bottleneck might be the endpoint devices that have to do the encryption/decryption.....  

But to answer your question....   "about" 2.5-3% of each packet is lost to the vpn config.   Then you need to allow for the other traffic that will flow .    Plus there's always the latency between endpoints.   So when speaking about pure packet overhead, 3% is a safe guess,  but overall bandwidth is different and the speed will be affected by latency and the encrypt/decrypt process....

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I've had to do a bit of research to setup my VPN connection so that Clients can access Windows Server 2008 network shares.  I have a Cisco ASA 5510 firewall.  I found an article which was extremely useful: It had a solution if you use ASDM to config…
OpenVPN is a great open source VPN server that is capable of providing quick and easy VPN access to your network on the cheap.  By default the software is configured to allow open access to your network.  But what if you want to restrict users to on…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
Windows 10 is mostly good. However the one thing that annoys me is how many clicks you have to do to dial a VPN connection. You have to go to settings from the start menu, (2 clicks), Network and Internet (1 click), Click VPN (another click) then fi…

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question