From nobody Sat Nov 4 09:20:04 2023 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4SMsX427Jtz50qnD for ; Sat, 4 Nov 2023 09:20:04 +0000 (UTC) (envelope-from ronald@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4SMsX41c54z3Cb3; Sat, 4 Nov 2023 09:20:04 +0000 (UTC) (envelope-from ronald@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1699089604; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z8fFOHmEn63xxeO/fpSVuv8R19HgmdzinV8LASGPeEw=; b=Dv2s95Te0iucL9em4aAjSwPgMihUNwbw1m44bWWcZVUiDtWpfLda9Dd6n/KkfTprDOo0+6 EEVMaZZthutdBVPE1zE2bzUaE+oX0XRYatZnZ9QcWxI/k+zvQ5j8wx9+qPK2KwYo6qbC1N 5ghNhZVlhLGE/g9+NNv6oN7ZGc++oOrhikqDtw6nFTuulUfLEspuAG2nUZNnFg7GtvjjnP 5SvD9NbLCxfZxYm6KEXdOjESPZJQSBp0btmbGSWr0ImdtxVoX6feDkqf3zcS9XHii3l9aX Gsm+iysYKlD5yK4gceYOzsaYZWPxssHQc3mtarbMpnuezsbTTS1cRYiNYCflsA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1699089604; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z8fFOHmEn63xxeO/fpSVuv8R19HgmdzinV8LASGPeEw=; b=fKyL5+mwdixm/mrwD05x0ac2oJ7orb0gi0nYtDv9ppM5BUJFKbYNGMmPFZ+TpwxYMVYxfp Atn4q/uXw94n0WPpytmNBm/9f3KewvDJ7vT2f9o0Z+zktIVSgKrPm8CaIJjZstNJIzpjul H8OnSSpLBigB7k9mUp2KAwrky0aAK4ZiPNscX/grhVOfy/9+jUl/yL1cH1MbE2Id1HD0iN KKEkLWeHAEDThehFHVmosuGiGuXT1nJYZjsiscwI9si8EW8RF4/6h6LjFHEydpQtCecI5V kyQAcCRDIjP7sGcfKv1StdmuSS8HJixyzJs3leUA5XAo0Mbf2I+84Mr23CJ7sg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1699089604; a=rsa-sha256; cv=none; b=vRGdiKevCQ9L9Kw4GxjKsUyVvY80KrQ9M9tEHUY+EmWMqDKLLGUMfRhb6vJH3+ZsTrzVkl VKPu9q67GquI6AcTOWR7AHAb5NzL2t1M6tB7xnRh5s+M4ZwJ0DzaKGsNM5E+GyIzbqQWOi Ao3RxFiha18m2w5oJR2er0c0o95d800XmJxUHfHiYwpIV5ZWNKWxalnyKPjhdostusRxnz HE0KQC+SebQkURQsRxBtYepGFSLrTU3gSCv8tGYwyZdcyPfYoRrVxSfAvHuJvqMN7abEPl y8P9DstgQyOCMFD4WQ4TTRO4mil8MQOFwgzjmj5UGEnGjYsa0dZuJQT967+rJQ== Received: from [192.168.1.109] (84-105-120-103.cable.dynamic.v4.ziggo.nl [84.105.120.103]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: ronald/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 4SMsX35Qmdz19Hy; Sat, 4 Nov 2023 09:20:03 +0000 (UTC) (envelope-from ronald@FreeBSD.org) Message-ID: <2baf7bc1-466c-4004-b77d-72b9fddfd6e7@FreeBSD.org> Date: Sat, 4 Nov 2023 10:20:04 +0100 List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Network starvation question Content-Language: en-US To: Yuri , "freebsd-net@freebsd.org" References: <8a967a3e-ef9c-4bc7-93e4-a5bca52ba9cf@FreeBSD.org> From: Ronald Klop In-Reply-To: <8a967a3e-ef9c-4bc7-93e4-a5bca52ba9cf@FreeBSD.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/4/23 03:37, Yuri wrote: > Router is also involved, and the provider's network as well. > > > But I think that there is a bug in the FreeBSD's network code that it allows a slower TCP connection to be hammered like this, unless there is a good explanation for this observation. > > > > Yuri > > > As you mention router and provider network are involved my first thought is bufferbloat. See https://en.wikipedia.org/wiki/Bufferbloat As UDP is involved FreeBSD doesn't do any flow control on that traffic and just sends as much as the application requests it to do. This is not a bug in FreeBSD. The design of the application is to requests FreeBSD to do this by using UDP instead of TCP. A solution to this would be to limit bandwidth of application A (mentioned in your original mail) to leave just enough space for application B to perform well. Maybe the application has support for this. Otherwise a mechanism like "dummynet" (in combination with ipfw firewall) can do this. Regards, Ronald.