Re: [manet-dlep-rg] Slight issue with Data items

Henning Rogge <> Mon, 10 March 2014 19:23 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 9AB2B1A065B for <>; Mon, 10 Mar 2014 12:23:45 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2
X-Spam-Status: No, score=-2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, SPF_PASS=-0.001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id HhOUQt5xG9hJ for <>; Mon, 10 Mar 2014 12:23:43 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:400d:c01::229]) by (Postfix) with ESMTP id 4641B1A0643 for <>; Mon, 10 Mar 2014 12:23:40 -0700 (PDT)
Received: by with SMTP id i17so8377427qcy.28 for <>; Mon, 10 Mar 2014 12:23:34 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; bh=vgdVWyIIq+LDVs50g4Zh+JwkHEr1RL/GXylZFSM9vIA=; b=k9KQXbqZL8Zn2sIE0Jt1MgNgIG0iayYSgAX3NBLFzUGzHGhghhtEB3YWWL3bRWWhbe +u1J2qAb+617xUgOa9KrObVR78JtTTyHFs7Sg28WIUxIF3a/j5JkznPODu1hKCHg4GX4 GB55uwySOvRv5aNV73UY0KiaX9KPknvxlfJT7qTgjGxb9WodvROIq51a52yPmZqXz68n 1jZCDY+A1e15YweH+H4i227L/z2e/udPaDjefXDv+/mCiQbrXXL2QE/BB3SUpXJzk9SP +U1zZn8lrXN5ascKhODUqUgTlL3XB6UffxxigJDmspfaJohhr8uxT5s+LopcClb1joVS L40A==
X-Received: by with SMTP id i8mr4566619qaz.96.1394479414763; Mon, 10 Mar 2014 12:23:34 -0700 (PDT)
MIME-Version: 1.0
Received: by with HTTP; Mon, 10 Mar 2014 12:23:14 -0700 (PDT)
In-Reply-To: <>
References: <> <d5a2b437-1a21-4569-9b97-5048512604bc@SUCNPTEXC01.COM.AD.UK.DS.CORP> <> <>
From: Henning Rogge <>
Date: Mon, 10 Mar 2014 20:23:14 +0100
Message-ID: <>
To: "Stan Ratliff (sratliff)" <>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Cc: " Group, \(\)" <>, Rick Taylor <>, "Taylor, Rick" <>
Subject: Re: [manet-dlep-rg] Slight issue with Data items
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DLEP Radio Group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 10 Mar 2014 19:23:45 -0000

Don't we already have a list of "mandatory/optional" data items for each signal?

Maybe we should reword "unknown" into "neither defined as mandatory or
optional for a signal" ?

Henning Rogge

On Mon, Mar 10, 2014 at 6:52 PM, Stan Ratliff (sratliff)
<> wrote:
> On Mar 10, 2014, at 1:25 PM, "Taylor, Rick" <> wrote:
>>> I'll offer up a slight modification of the "London Rule" :  Experimental Data
>>> Items (and Vendor-specific TLVs) that are not supported by an
>>> implementation should be parsed (e.g. "stepped over') and silently dropped.
>>> Data Item TLVs that are not *understood* (e.g. TLV number not registered,
>>> or "reserved"), OR are out-of-context (like a Version TLV in a destination
>>> update message) should cause PEER_TERMINATION and closure of TCP
>>> session.
>> That will rely on a clear list of every suitable data item TLV used with each signal, which might turn into an O(N^2) documentation nightmare.
>> I was wondering about adding an 8bit context field to the TLV header: 8bit Type, 8bit Context, 16bit Length (seems to align nicely).
>> Context: 1 = Discovery Data Item, 2 = Session Initiation/Termination Data Item, 3 = Peer Data Item, 4 = Link Data Item, plus the classic experimental and reserved spaces.
>> This might be easier to specify, and reduces the London Rule to "Any data item received with a context field that does not match the context of the enclosing signal MUST result in PEER_TERMINATION", then all that is needed is to define the context of each signal, back to O(N) for those of you familiar with big-O notation.
> Hmmm... could be. Let me noodle on this a bit.
> Regards,
> Stan
>> I know this seems like adding error checking to the protocol, but with Vendor Extensions and experimental TLVs a bit of error checking is no bad thing, just think of it as an FEC code...
>> Alternatively you could consider Type and Context as one little endian 16bit value... or swap them around to make CTLV...
>> Rick
>> The information contained within this e-mail and any files attached to this e-mail is private and in addition may include commercially sensitive information. The contents of this e-mail are for the intended recipient only and therefore if you wish to disclose the information contained within this e-mail or attached files, please contact the sender prior to any such disclosure. If you are not the intended recipient, any disclosure, copying or distribution is prohibited. Please also contact the sender and inform them of the error and delete the e-mail, including any attached files from your system. Cassidian Limited, part of the Airbus Defence and Space division. Registered Office: Quadrant House, Celtic Springs, Coedkernew, Newport , NP10 8FZ. Registered in England and Wales under company number 04191036
> _______________________________________________
> manet-dlep-rg mailing list