Design: Ignored Unknown Frame Types and Intermediaries

James M Snell <> Sat, 11 May 2013 15:30 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 4FAD821F9397 for <>; Sat, 11 May 2013 08:30:31 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -10.409
X-Spam-Status: No, score=-10.409 tagged_above=-999 required=5 tests=[AWL=0.190, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id Y7Mzcirf+WHA for <>; Sat, 11 May 2013 08:30:25 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 0F72621F9347 for <>; Sat, 11 May 2013 08:30:24 -0700 (PDT)
Received: from lists by with local (Exim 4.72) (envelope-from <>) id 1UbBj1-0004F4-5f for; Sat, 11 May 2013 15:28:43 +0000
Resent-Date: Sat, 11 May 2013 15:28:43 +0000
Resent-Message-Id: <>
Received: from ([]) by with esmtp (Exim 4.72) (envelope-from <>) id 1UbBil-0004Dx-2W for; Sat, 11 May 2013 15:28:27 +0000
Received: from ([]) by with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.72) (envelope-from <>) id 1UbBik-0002DM-Ir for; Sat, 11 May 2013 15:28:27 +0000
Received: by with SMTP id ta17so1721648obb.26 for <>; Sat, 11 May 2013 08:28:00 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=x-received:mime-version:from:date:message-id:subject:to :content-type; bh=CjX0/NvxCfiQlFnbev2kB/Tv2DsEN79twTzSIc5a3Kc=; b=NX1jffAfvWXKjiMaKA83nFsi0NHU2i088bPmdzZaGdxAzZ0AGpeLsPP8JSDHHNv1VF JC6Azo3hfWZgpbASjOUGlx3Jai8+qKIe50G0la/R+XzKlnyCUKI3+vesjBiyFNRp6VQy 7fnXjYY+0gyI4+U6VA0H97rFnKNeXHmeyaBLwRWAo/uLuMn2YwMOfFAUPwShUQsMLnka fv3nkHF1dHqkgJCiHG62lgcf0ghYV3tir3oFFdL51Fk58qgz0Bqfqb7suebzOhH6QsMx NMwhfTvX79ielRFQZCKgs0v75uePmS+E+jUtTCu0BLWuwmFtnEYYK1TCxfKTt4cwKck3 McoQ==
X-Received: by with SMTP id hl5mr9323137obb.33.1368286080610; Sat, 11 May 2013 08:28:00 -0700 (PDT)
MIME-Version: 1.0
Received: by with HTTP; Sat, 11 May 2013 08:27:40 -0700 (PDT)
From: James M Snell <>
Date: Sat, 11 May 2013 08:27:40 -0700
Message-ID: <>
To: "" <>
Content-Type: text/plain; charset="UTF-8"
Received-SPF: pass client-ip=;;
X-W3C-Hub-Spam-Status: No, score=-3.5
X-W3C-Hub-Spam-Report: AWL=-2.702, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001
X-W3C-Scan-Sig: 1UbBik-0002DM-Ir 484a5ada7f8396752afde42745ddbc5c
Subject: Design: Ignored Unknown Frame Types and Intermediaries
Archived-At: <>
X-Mailing-List: <> archive/latest/17949
Precedence: list
List-Id: <>
List-Help: <>
List-Post: <>
List-Unsubscribe: <>

In the current draft, endpoints are required to "ignore" unknown and
unsupported frame types. What's not yet clear, however, is whether
such frames are required to be forwarded on by intermediaries that do
not support them.

In other words, A talks to C via reverse proxy B. A sends a stream
that includes EXTENSION_FRAME_TYPE that is unknown to B. Is B...

A) Required to drop the frame silently without forwarding it on to C
B) Required to always forward the frame on to C
C) Neither, B can do whatever it wants

There is an obvious impact here on the future deployment of new
extension frame types. If the answer is A or C, we'll have to wait on
infrastructure support to use new frame types, which would be

- James