The problem I'm having is Skype is not impossible to detect, but it is  
difficult and some QoS mechanisms miss it because it's designed to be  
hard to detect and stop so it can slip out networks where the admin  
tries to block IM apps. The better network security devices and detect  
and filter or QoS it. But Skype doesn't use TOS or other QoS  
prioritizing bits and it greatly varies the ports it uses in an effort  
to not reveal itself. It's really quite amazing, if you have an  
internet connection but you have a DNS issue (no DNS info being  
propagated by DHCP for example) it will still find it's way out and  
connect. It's one quick indication of a good network with bad DNS.

Another problem is the newer P2P apps do likewise (random ports,  
nondescript packets/data) in an effort to prevent ISP operators from  
blocking or limiting it. So it's a continual game of cat and mouse  
between the program authors and the net admin folks trying to detect  
and control these things.

Greg

On Feb 13, 2009, at 9:59 AM, Eric Rogers wrote:

> Have you done any packet captures?  If it is a small site, you might  
> be
> able to look at the TOS bit and prioritize accordingly.  If you see a
> DSCP (TOS) of 46, I assume it is VoIP and tag it for queues.  In
> Mikrotik, there is a "connection type" option, and SIP is one of the
> options.  I also tag that one and set it to VoIP for the QoS rules.
>
> It gets most traffic, but don't know about Skype.
>
> Eric
>
>
> -----Original Message-----
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org]  
> On
> Behalf Of os10ru...@gmail.com
> Sent: Friday, February 13, 2009 8:18 AM
> To: WISPA General List
> Subject: [WISPA] RouterOS x86 for Skype QoS?
>
> Does anyone have experience using RouterOS (on RouterBoard or x86) for
> doing Skype QoS? I've been trying many different Linux based servers
> (ZeroShell, pfsense, Endian, ClarkConnect specifically for achieving
> good QoS with Skype - more specifically to keep the P2P stuff from
> killing Skype - and so far nothing is performing as well as little
> router with Tomato firmware and it's QoS. The problem is having the
> layer 7 sniffer properly detect and categorize Skype and uTorrent. I'm
> getting ready to try RouterOS (x86) and Wolverine.
>
> Does anyone have any success stories?
>
> Thanks!
> Greg
>
>
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