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From: David Miller <davem@davemloft.net>
To: ilpo.jarvinen@helsinki.fi
Cc: netdev@vger.kernel.org
Subject: Re: TCP's initial cwnd setting correct?...
Date: Tue, 07 Aug 2007 18:28:23 -0700 (PDT)	[thread overview]
Message-ID: <20070807.182823.123919803.davem@davemloft.net> (raw)
In-Reply-To: <Pine.LNX.4.64.0708061508070.8788@kivilampi-30.cs.helsinki.fi>

From: "Ilpo_Järvinen" <ilpo.jarvinen@helsinki.fi>
Date: Mon, 6 Aug 2007 15:37:15 +0300 (EEST)

> @@ -805,13 +805,13 @@ void tcp_update_metrics(struct sock *sk)
>  	}
>  }
>  
> -/* Numbers are taken from RFC2414.  */
> +/* Numbers are taken from RFC3390.  */
>  __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst)
>  {
>  	__u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
>  
>  	if (!cwnd) {
> -		if (tp->mss_cache > 1460)
> +		if (tp->mss_cache >= 2190)
>  			cwnd = 2;
>  		else
>  			cwnd = (tp->mss_cache > 1095) ? 3 : 4;

I remember suggesting something similar about 5 or 6 years
ago and Alexey Kuznetsov at the time explained the numbers
which are there and why they should not be changed.

I forget the reasons though, and I'll try to do the research.

These numbers have been like this forever, FWIW.

  parent reply	other threads:[~2007-08-08  1:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-06 12:37 TCP's initial cwnd setting correct? Ilpo Järvinen
2007-08-06 18:31 ` Ilpo Järvinen
2007-08-08 15:26   ` John Heffner
2007-08-08  1:28 ` David Miller [this message]
2007-08-08 15:20   ` John Heffner
2007-08-09  4:40     ` David Miller
2007-08-08  5:01 ` David Miller
2007-08-08 13:05   ` Ilpo Järvinen

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