[LARTC] Re: LARTC digest, Vol 1 #766 - 9 msgs

[LARTC] Re: LARTC digest, Vol 1 #766 - 9 msgs

[Leonardo Balliache]

Hi,

In a busy network you need to use prio. Check how many channels of voice 
you do need and bandwidth required by each channel (16-32 kbits?). Put 
voice (udp packets) in the higher priority prio queue and use tbf behind it 
to limit traffic via prio to the maximum required for your channels. Or use 
htp putting your udp traffic in the higher priority class.

Be careful that higher prio traffic can't be more than 20-30% of the link 
capacity to avoid starvation of lower prio traffic.

Don´t expect good quality in a busy network. When congestion appears your 
udp packets will be dropped with no mercy (udp is an unresponssive 
protocol) hurting quality.

Best regards,

Leonardo Balliache

Ps: Cisco has (check your IOS version) RTP header compression that can help 
a lot to lowering bandwidth requirements. You have to enable it at both 
sides of the link. Also, why don't try directly with Cisco PQ?

At 06:28 a.m. 17/09/02 +0200, you wrote:
>From: Andreani Luca <landreani@seltatel.it>
>To: "LARTC mailing list (E-mail)" <lartc@mailman.ds9a.nl>
>Date: Mon, 16 Sep 2002 11:49:28 +0200
>Subject: [LARTC] Voip and Qos tests
>
>Hello list,
>
>I'm performing some tests in order to evaluate the possibility to make Voip
>calls on a busy network.
>I use some cisco routers with wfq enabled. I want to introduce some linux
>boxes acting as routers.
>I am especially interested in low-speed (64-128 kbps) links with PPP and
>frame-relay.
>
>Haw you some reference about similar tests?
>
>Whath qdisc (from tc) has best performance in these situations?
>
>Thank's
>
>Luca



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