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From: Patrick McHardy <kaber@trash.net>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Jarek Poplawski <jarkao2@gmail.com>,
	David Miller <davem@davemloft.net>,
	herbert@gondor.apana.org.au, netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] sch_netem: Remove classful functionality
Date: Tue, 04 Nov 2008 12:04:24 +0100	[thread overview]
Message-ID: <49102C38.5070207@trash.net> (raw)
In-Reply-To: <20081103090630.40b645d2@extreme>

Stephen Hemminger wrote:
> On Mon, 03 Nov 2008 12:20:25 +0100
> Patrick McHardy <kaber@trash.net> wrote:
> 
>> Whats wrong with simply using TBF as parent qdisc of netem?
> 
> It works but does something slightly different.
> 
>    netem inside TBF is like long delay network followed by choke on last hop
>    TBF inside netem was like choke on uplink followed by long delay network.

The behaviour visible on either side is identical though.

TBF only affects the ->dequeue path, in which netem only handles delays.
In both cases the total delay is the maximum of the absolute delay
imposed by netem + the delay resulting from rate-limiting (the maximum
because TBF can recharge while netem is delaying). Both values are
independant from each other, so the maximum is always the same.

      parent reply	other threads:[~2008-11-04 11:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-31 13:20 [PATCH 1/2] sch_netem: Remove classful functionality Jarek Poplawski
2008-10-31 16:45 ` Stephen Hemminger
2008-11-02  7:37 ` David Miller
2008-11-03  8:29   ` Jarek Poplawski
2008-11-03 11:20     ` Patrick McHardy
2008-11-03 17:06       ` Stephen Hemminger
2008-11-04  9:56         ` Jarek Poplawski
2008-11-04 16:25           ` Stephen Hemminger
2008-11-04 21:42             ` Patrick McHardy
2008-11-04 11:04         ` Patrick McHardy [this message]

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