QOS over VPN

I have a couple of Cisco 515e PIX firewalls with vr 7.2 of the PIX software, which supports QOS through a VPN. I have QOS configured but am having issues with VOIP calls being dropped and sounding really broken up. Someone has told me that I need to change the QOS paramaters to fix the issue, however I don't see how that could be the issue.

My question which I can't find a good answer too at the Cisco web site (or anywhere else on the net) is simply this... If I configure QOS that only applies on the inside interfaces of both Pix's and it will have no effect on the actual tunnel trafic just on the tunneled traffic at either end right?

I think the whole idea of VPN through an internet connection will never be able to reliably deliver voice unless the ISP has some private network that they can control.

Any thoughts or documentation on this issue would be appreciated.

Reply to
jagbag4
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Well, first, I must say that you are incorrect about not being able to ever get good calls over the internet. I personally have had home voip phone service for about 3 years now and see no reason to go back to a traditional telco line. There are many other people hopping on board as well. Look at all the companies popping up out there, Viatalk,Vonage, Sunrocket, Skype, Packet8 and many more. Through vpn isn't much different. You just need to make sure that you have the horse power to process the packets quickly enough. I wouldn't think this would be a problem with the Pix 515.

That said, there are things to consider and it may be possible that you don't have a good path from one end to the other. QOS is very important. I'm not sure how this is handled on the pix, but on the cisco routers, you would do a pre-classify on the packets before they enter the tunnel, so that the qos is carried across the vpn. Otherwise, make sure that you reclassify the packets as they are coming in. Also, be sure that you are running g.729. If you are using g.711 that could be a big part of the problem.

Voip over the internet is here and it is, generally speaking, reliable. So, you'll just need to troubleshoot where the problem is occuring for you.

Hope that helps,

Jim

Reply to
Scooby

I don't know why you would run VoIP *through* VPN, but I've had very good experience using ViaTalk through a WRT54G router having VPN

*alongside* VoIP using QoS, i.e. if VPN and VoIP traffic happen at the same time, VoIP is given the preference. VT tech support was very helpful helping me through some initial issues, you might want to give them a call and see if they support your setup, they might have run into the same situation already.

Thanks,

Thomas

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Reply to
Thomas

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