Traffic Shaping

Hi, i have tryed alot of firewall now, clarkconnect, smoothwall, and some others, but i cannot find a Traffic Shaping system, so i can add the ip for my ip-phone and then the ip-phone gets the traffic it needs when someone calls(up and download), i have seen this on the linksys routers but never on server firewall, i want this, since then i can download when i want, and when someone calls me the download and upload goes down so i can take the phone, hope someone can answer this. thanks.

PS: My English isn't the best

Daniel:)

Hi Daniel,

i have succesfully setup my m0no to prioritize VoIP over the rest. Just calculate the percentage of bandwidth needed by your VoIP device. Create a queues with this percentage as weight. Create apprpriate rules so that every traffic of your VoIP device gets into those queues. Make sur the sum of all your weights do not exceed 100.
Also make sur that you do not get to optimistic when setting your pipes bandwidth.
This is what i found by experimenting with my own configuration, result might differ........

thanks for an good answer, i will try m0n0wall when im getting home from school, im using smoothwall now, but its god an problem with QoS and uploadspeed + usenet newsleecher, so i hope this will work better.

Here is a detailed, almost step-by-step guide that may help to setup VoIP shaping on m0n0

 http://blog.mgraves.org/2008/01/11/successful-voip-over-dsl-part-4-traffic-shaping/#more-69

m0n0 has become the only way i got my voip working perfect while still being able to use internet normally. seems need at least 100k up/down dedicated to voip. any less you get the static and drop calls. i set mine to 120k up/down and never any glimpse of problems.

I've tried using queues to shape VoIP traffic, but the only problem is fluctuations in available bandwidth. So if you have a 1.5 Mbps Down 384 Kbps Up connection and your VoIP phone uses 90 Kbps for calls, you are better off just creating a custom pipe for your VoIP (to avoid all the queue mess) and assigning your VoIP phone to that strictly for both upload/download.

Then on your regular traffic shaping rules, just make sure your pipes are 1.5 Mbps - 90 kbps for both Upload and Download. So your pipe for Download would be 1.4 Mbps D / 294 Kbps U for the pipes values. It's true you'll always be missing that 90 kbps, but the calls are so much more trouble free this way. The VoIP traffic will in theory never go higher than what it always does so it shouldn't overrun the saturation of the link. Since everything is being shaped to under 1.4 Mbps / 294 Kbps, you VoIP data can fly through m0n0wall more quickly without the queues and rules slowing it down (vital for realtime talk anyway).

That's just my take on it. Some m0n0walls traffic shape better than others, it depends on how good your ISP is at providing the "advertised" speed that you have purchased.

This came out a while back, but seems to be relevant here: http://ipcommunications.tmcnet.com/hot-topics/advanced-signaling-solutions/articles/6414-voip-call-quality-hindrances-meet-netequalizer.htm

Some m0n0walls traffic shape better than others, it depends on how good your ISP is at providing the "advertised" speed that you have purchased.

The critical part about traffic shaping for VOIP is that you never, never, never (truly) never actually saturate your connection to your ISP in either direction. That means knowing for a fact what your worst case, actual available bandwidth will be. Your ISPs claims aren't worth mentioning. You need to measure it yourself.

In my case I measured using several speed test sites, at different times of the day, then took the worst case results as the basis of my traffic shaper setup. It seems wasteful at first, like there's bandwidth available that you will never use. However, it really does work. I have a complex VOIP setup, a mix of a local IP-PBX and hosted services, and it all works very reliably.

FWIW, consider also using a reduced bandwidth codec. I like G.729a  a lot. I use it both on my Asterisk box and on my Polycom & snom phones with OnSIP.

Yes, technically the call quality is a little less than G.711. However, the complaints people commonly make about VOIP call quality are more often than not a reflection of poor bandwidth management than poor codec selection.

By using a low bit rate codec you de-emphasize the requirement for precision traffic management. It gives your some room for error. This is especially true on asymetrical links like DSL or cable modems.

I'm hoping to do a screencast recording this coming weekend to document the process from end-to-end. I'm setting up another m0n0wall on a Comcast cable modem. Thus I have to go through the entire process again, so it's a good opportunity to give a detailed account of how it's done.

Michael

I finally found some time to create a screencast documenting my traffic shaping setup for a VOIP based home-office. You can find that here:

http://m0n0.ch/wall/screencasts.php

Manuel had a few suggestions for an alternative setup. I'm going to try them myself and see how they work.

Michael

Any update on Manuels other examples

Bobby W
Small Business VoIP
Business Telephone Systems

Michael,

Great work with the screencast.  It is great to see the traffic shaper set up step by step.  I do have one question about the configuration you used in the video.

In the video you set up dedicated pipes for inbound and outbound VoIP traffic.  Doesn't this mean that the bandwidth is always reserved for those pipes?  So if there are no VoIP calls in progress that bandwidth is not available for other uses.  Is that correct?

Michael,

Great work with the screencast.  It is great to see the traffic shaper set up step by step.  I do have one question about the configuration you used in the video.

In the video you set up dedicated pipes for inbound and outbound VoIP traffic.  Doesn't this mean that the bandwidth is always reserved for those pipes?  So if there are no VoIP calls in progress that bandwidth is not available for other uses.  Is that correct?

Yes, pipes are dedicated, but if you stack two side by side, (voip pipe and then everything else pipe), technically bandwidth will be split between them, even if it's uneven.

So if you have a 1 MB link and you set one pipe for 100K for your VoIP and 900K for everything else, you'll always be missing that 100K.

Now if you make a 100K and 1000K pipe on the 1 MB link, then technically they overlap because if both were going full stream that would be 1.1 MB What ends up happening will be the same as if you had both of them in 1 pipe sharing the bandwidth, no benefit if you overlap them for VoIP.

The only way to make that bandwidth available when the VoIP is not in use would be to use one pipe and just set the VoIP traffic to the highest priority and hope for the best. The closer you are to the real world bandwidth limits of your connection, the better it works. But since just about any ISP flux all over the place, the pipes make it easier than doing infinite tweaking of your pipe/queues to make it work.

Hello again, long time since i posted this thread, and i have found out that the best firewall for my use, is monowall, its a pretty great firewall, it works great for all the things i need, traffic shaping, works great, finaly my mothers can talk in the ip-phone when i download, the only problem now, is the damn youtube upload videos my sisters using:P


anyway, tnx for monowall! hope it will come more and greater futures in the future:)