Re: [quicwg/base-drafts] Describe PMTU probing that includes source connection ID for routing … (#2402)

MikkelFJ <notifications@github.com> Wed, 06 February 2019 13:16 UTC

Return-Path: <bounces+848413-a050-quic-issues=ietf.org@sgmail.github.com>
X-Original-To: quic-issues@ietfa.amsl.com
Delivered-To: quic-issues@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id DB54F12875B for <quic-issues@ietfa.amsl.com>; Wed, 6 Feb 2019 05:16:42 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -7.553
X-Spam-Level:
X-Spam-Status: No, score=-7.553 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-4.553, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=github.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cDBpuxUUQQRN for <quic-issues@ietfa.amsl.com>; Wed, 6 Feb 2019 05:16:41 -0800 (PST)
Received: from o11.sgmail.github.com (o11.sgmail.github.com [167.89.101.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 35B2B126CB6 for <quic-issues@ietf.org>; Wed, 6 Feb 2019 05:16:41 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=github.com; h=from:reply-to:to:cc:in-reply-to:references:subject:mime-version:content-type:content-transfer-encoding:list-id:list-archive:list-post:list-unsubscribe; s=s20150108; bh=JwWP3lskJ5bfVm3a1gsrTq7RA5c=; b=dMsJAMBUzOPnm7PH YODzObJ1u9oRzQMR1pxp5tx/FvNk+uZ2clxJBjaMiKJgXEdKmbGTCooLOyfrNAf7 nLxncFKNaiZ1YXJMjO1+C+aeP00j67tUi1BoeaPU8in/6Y4H5sx2BeLgsTukltLL 2lzw5RwSIoN+7w3ebQll556YLc0=
Received: by filter1777p1mdw1.sendgrid.net with SMTP id filter1777p1mdw1-475-5C5ADE37-10 2019-02-06 13:16:39.44148877 +0000 UTC m=+58637.862436232
Received: from github-lowworker-e8fa9ff.cp1-iad.github.net (unknown [192.30.252.43]) by ismtpd0046p1iad1.sendgrid.net (SG) with ESMTP id 35DAX88DSsCJIz4sCJZEeg for <quic-issues@ietf.org>; Wed, 06 Feb 2019 13:16:39.332 +0000 (UTC)
Received: from github.com (localhost [127.0.0.1]) by github-lowworker-e8fa9ff.cp1-iad.github.net (Postfix) with ESMTP id 5124042033E for <quic-issues@ietf.org>; Wed, 6 Feb 2019 05:16:39 -0800 (PST)
Date: Wed, 06 Feb 2019 13:16:39 +0000 (UTC)
From: MikkelFJ <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab74f6143b5b0fe345026f10151d8f91b6c720e3c992cf000000011872a03792a169ce1833165d@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2402/c461019172@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2402@github.com>
References: <quicwg/base-drafts/pull/2402@github.com>
Subject: =?UTF-8?Q?Re:_[quicwg/base-drafts]_Describe_PMTU_probing_that?= =?UTF-8?Q?_includes_source_connection_ID_for_routing_=E2=80=A6_=28#2402=29?=
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5c5ade374f6fd_1ac33fc38c0d45b41060e6"; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: mikkelfj
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
X-GitHub-Recipient-Address: quic-issues@ietf.org
X-SG-EID: l64QuQ2uJCcEyUykJbxN122A6QRmEpucztpreh3Pak1JCzVRza62OUPjr8hx30TcNEDZOs5mPFSVjK Un9LF9xiNE2DUI05fQR0zsF0//2PgO7sazpbItU76nLkJ2S7591GEiJADfRnawgZvckD4C/psFjeM3 afyFq2VyCOPEHJlyURkLqD5vjPJZFa/oePGHu2qj2ZXER0wBHcN9Ou3+Kw==
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic-issues/2N0z_UR7ZG4bK1SQb4WxJZqXzCc>
X-BeenThere: quic-issues@ietf.org
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <quic-issues.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic-issues/>
List-Post: <mailto:quic-issues@ietf.org>
List-Help: <mailto:quic-issues-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 06 Feb 2019 13:16:43 -0000

> The probe is a part of the connection. Otherwise it will not elicit an ACK of the coalesced short packet.
But it will use a dedicated connection ID.

> I am a bit confused that we are discussing the cost of a single if statement.

Yes, but it still impacts the design because the first thing I would do would be to look up bytes 1-4 in a hash table and call a handler function that has no context for handshake. So it will now have to add an indirection and process packets it does not understand. It can't be the same logic as the one that handles handshakes, because it would start by verifying the packet.

Or that initial lookup would would have to first check the packet type and go slow path, but the context must be looked up by ID, and the general slow path expects context, or it will drop packets. But you can't do that here, because there is no context. So you have to special handle that.

So performance-wise it would be survivable, just pretty ugly.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/2402#issuecomment-461019172