[Asterisk-Users] QoS for improvements

[Michael Graves]

Sometimes this all sounds so complicated....but it needn't be. I
suppose it can vary with the size of your installation.

I use a m0n0wall router on a Covad DSL line. Using m0n0's traffic
shaping feature I establish inbound and outbound pipes which are
bandwidth restricted to just less than my mesured average DSL rate.  I
then break my traffic into three priority ques in each direction;
highest priority, medium priority, low priority.

I assign all IAX traffic in/out to the highest priority que, and map
all IAX ports to the * server inside the LAN.

In fact, I just used the Magic Shaper Wizard in m0n0, then added IAX
specific entries to give it highest priority. The whole process took
about a half hour. Just as easy as the Linksys BEFSR-81 that I had
before, but more reliable and more controllable.

Now to be fair, I only have about 6 phones. I use IAX2 to all my ITSPs
and SIP in-house only. My DSL is 3M down / 768k up.

Michael

On Fri, 06 May 2005 08:37:20 +0200, Jean-Christophe Heger wrote:

>I've spent may hours to play with HTB QoS settings on the firewall, but with absolutely no effect. In fact, this is normal, because the time required to let a data packet going through the ADSL line will break the voice jitter. The only right way to handle this issue is to modify the MTU on the router.
>
>Without setting a TOS for voip, data where going through and voice was unusable.
>With a lowdelay (0x10) TOS set for voip, voice was going through, but data was blocked.
>With a lowdelay TOS and an HTB QoS on the router, data where going through slowly and voice was scambled.
>
>After many tests, an MTU of 700 did work quite well. I did loose 15% of bandwidth for data (twice more overheads), but data and voice may be used together.
>
>Those tests have been done on a 256 kbps up stream.
>
>There is a quite good explenation about this issue on Cisco's web
>site, and about they're LFI technology (link fragmentation and interleaving):
>http://www.cisco.com/warp/public/788/voice-qos/voip-mlppp.html#link_frag
>
>Jean-Chrsitophe
>
>
>
>
>Kumara Jayaweera a écrit :
>
>>Hello! Everybody!!,
>>I want to run VoIP in the same LAN (15 windows clients) which we use for
>>surfing the Internet. 6-7 softphones in the same client's machines is 'the
>>target'. My DSL is 128kbps, (I can go to 256kbps if required). So, I am told
>>to install some QoS's in the LAN to improve the voice quality. Frankly, I
>>don't know what it (QoS= Quality of Service) is. I hope you may help me
>>giving "Links" to read and briefing me your ideas.
>>Thanks to everybody in the list.
>>So far my success and progress are your help.
>>Thanks again
>>Kumara
>>
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--
Michael Graves                           mgraves at pixelpower.com
Sr. Product Specialist                          www.pixelpower.com
Pixel Power Inc.                                 mgraves at mstvp.com

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