ziphnor
join:2008-05-04
| [XP] Quality of service with VPN?
Hi,
At home i have 3 computers and various wireless network devices. One computer connects to the internet via a VPN connection and is used for P2P traffic.
My first problem is that on the latter computer, browsing and similar is horribly slow, because the P2P traffic uses the full capacity of the VPN connection. I would very much like to decrease the priority of the P2P traffic.
My current router does not support any kind of QoS as far as i can see, but my guess is that even if it did, it wouldn't help because it cannot see inside the encrypted packets of the VPN connection?
My first question is therefore: What can i do on the aforementioned PC, does Windows XP have some kind of QoS or similar build-in perhaps?
Secondly, while the VPN bandwidth is usually somewhat less than my ADSL connection, sometimes the other PCs and devices are also adversely affected by the traffic on the VPN. Does there exist any routers which could help me with this problem?
Thanks for reading. |
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LLigetfa
join:2006-05-15
Fort Frances, ON
| You need to understand how QOS works in order to understand where it can work. It only works where there is a confluence of data at a congestion point and QOS is running at that congestion point. If the congestion point is somewhere out on the internet, QOS will not somehow magically flag your packets with the "immunity" flag.
There is QOS available on XP. It will priorize traffic (the confluence being the NIC) but since the NIC is not your major bottleneck, it will do you no good.
Your router does present a congestion point and running QOS on it can help but as you surmised, P2P cannot be singled out from the encrypted VPN stream. You would be treating the entire VPN stream.
Bandwidth shaping or arbitrating is probably what you are looking for but I doubt you will find anything decent running on a consumer router. That said, you could build something using linux or BSD. Look into bandwidtharbitrator, m0n0wall, and pfsense.
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Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey |
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ziphnor
join:2008-05-04
| Thank you for responding.
As you say, i dont really know how QoS works  However, i do have some idea of what i would like to happen 
As to analyzing before the congestion point (at the PC), i was assuming that this would be done by analyzing the TCP packets. By looking at these packets it should be possible to observe the amount of congestion occurring and consequently throttle the low priority traffic. Of course UDP traffic does not give this kind of information so it would probably be a worthless mechanism for applications like Skype etc. However, in my case the traffic is all TCP.
Anyway, I will try to look into bandwidth arbitration/shaping. |
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LLigetfa
join:2006-05-15
Fort Frances, ON
| Yes, of course QOS will force an orderly exit of the packets past that bottleneck that is between the motherboard bus and the NIC, but as I said before, it does not flag the packet with "immunity" to magically grant a higher priority on all the other bottlenecks downstream.
Most arbitration schemes look at source and destination to allocate a fairness to all traffic and the VPN will all be tarred by the same brush.
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Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey |
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