[icnrg] ICNLoWPAN: Discussion on Extensibility and Name Compression Scheme

Cenk Gündoğan <mail+ietf@gundogan.net> Mon, 19 August 2019 12:46 UTC

Return-Path: <mail+ietf@gundogan.net>
X-Original-To: icnrg@ietfa.amsl.com
Delivered-To: icnrg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 38D16120019 for <icnrg@ietfa.amsl.com>; Mon, 19 Aug 2019 05:46:56 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.699
X-Spam-Level:
X-Spam-Status: No, score=-1.699 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, FROM_EXCESS_BASE64=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=fail (2048-bit key) reason="fail (bad RSA signature)" header.d=gundogan.net
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 PJ-XdEnou4eO for <icnrg@ietfa.amsl.com>; Mon, 19 Aug 2019 05:46:54 -0700 (PDT)
Received: from mail.localdomain (trantor.gundogan.net [37.120.167.193]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 4AB25120013 for <icnrg@irtf.org>; Mon, 19 Aug 2019 05:46:54 -0700 (PDT)
Received: from localhost (unknown [141.22.28.153]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by mail.localdomain (Postfix) with ESMTPSA id 609C021A8B for <icnrg@irtf.org>; Mon, 19 Aug 2019 14:45:34 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gundogan.net; s=201712; t=1566218734; bh=mYTutJHCZOr2nT/7oxpVq4lEmM1ktsL9UwlQ6tYxnsQ=; h=From:To:Subject:Date:From; b=rgPuCldQasBFN0HnuBpAPNwZ7IUKTl1QQ1G7kfFYV772k+HOdBcnn2awGf6yt/QWZ 6pOztUcAQAuXb0j1jaZX8vizTkOJ6AOlk5qFOAsQeehe1egpD+UKXNF8ANWiO+RWeF QsRHmReQo7ILJssQItjkzbysFOP7Ci1Ki5AZnHP4fx+S1b4OEXlY2KkrC9+F0DbVgM UTFFq1Jw52w+cYyobT0YIIfcnPX5jrWRG3kCBo7PB6Gj6F4CN3sjXnU21WPBGReb/R RgnPUd2ylXZ3TNgMVvK/XzE137OYX1gHTgvsSGx7EdfdoAv+CS6btbOoaGNe/XqMgZ QLJRFPS1H3pSA==
User-agent: mu4e 1.2.0; emacs 26.2
From: Cenk =?utf-8?B?R8O8bmRvxJ9hbg==?= <mail+ietf@gundogan.net>
To: ICNRG <icnrg@irtf.org>
Date: Mon, 19 Aug 2019 14:46:50 +0200
Message-ID: <8736hxl3ut.fsf@gundogan.net>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature"
Archived-At: <https://mailarchive.ietf.org/arch/msg/icnrg/q5ReKBxCDCDFHiq42GVgT7S0l_E>
Subject: [icnrg] ICNLoWPAN: Discussion on Extensibility and Name Compression Scheme
X-BeenThere: icnrg@irtf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Information-Centric Networking research group discussion list <icnrg.irtf.org>
List-Unsubscribe: <https://www.irtf.org/mailman/options/icnrg>, <mailto:icnrg-request@irtf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/icnrg/>
List-Post: <mailto:icnrg@irtf.org>
List-Help: <mailto:icnrg-request@irtf.org?subject=help>
List-Subscribe: <https://www.irtf.org/mailman/listinfo/icnrg>, <mailto:icnrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Mon, 19 Aug 2019 12:46:56 -0000

Dear ICNRG,

in the last ICNRG meeting (Montreal), Thomas presented the current state
of the ICNLoWPAN [1] document. The conclusion of discussions during the
talk was to investigate whether a name compression scheme with relaxed
restrictions than the predefined one might be better suited. An idea
formed to support names with varying (but most frequently used) name
component types. For CCNx, these seem to be T_NAMESEGMENT, T_IPID, and
MAY include T_CHUNK [2] and T_VERSION [3]. For NDN, these seem to
include GenericNameComponent, TimestampNameComponent,
VersionNameComponent and SequenceNumberNameComponent [4]. Both lists are
by no means complete, as for both protocols new (frequently used) name
component types can still emerge.

As a reminder .. the currently defined name compression scheme as per
[1] has the following restrictions:

1) all name component types are elided and GenericNameComponent (NDN) /
T_NAMESEGMENT (CCNx) are assumed for all components. No other name
component types are expected.

2) name component lengths are restricted to 15 octets max, in order to
fit the length of two consecutive components into 1 octet.

Our initial motivation was to have a scheme that removes most of the TLV
overhead and our assumption was that IoT deployments usually use
machine-to-machine communications (which MAY carry less semantics in the
name).

To proceed with this discussion and to promote the progression of the
ICNLoWPAN document, we would like to propose the following:

In light of the flexibility and extensibility of CCNx / NDN, we would
also make the "compression octets" of ICNLoWPAN extensible. An example:
we would assign a bit in Figure 13+16 of [1] (respectively for CCNx) to
indicate a second, following octet to be part of the compression
algorithm. In this following octet, we can then allocate a number of
bits to (i) select a name compression algorithm (deviating from the
default) and (ii) define necessary compression parameters. Specific
definitions for (i) and (ii), and possible other things also, could then
be handled by future I-D documents as the need arises from new features
added to CCNx and NDN.

The questions I intend to provoke are:

(i) is the group O.K. with making ICNLoWPAN dispatches extensible?

(ii) should we think of a more elaborate name compression scheme as
default behaviour for ICNLoWPAN, or would the group be O.K. with keeping
the currently defined (highly restrictive, but very low-overhead) name
compression scheme provided in [1]? Other name compression algorithms
(e.g., static/dynamic dictionary-based approaches with proper dictionary
(re-)distribution; I believe Marc has some ideas on this) can then be
added to the ICNLoWPAN extension octet via new I-Ds once mature ideas
exist.

Best,
Cenk

[1] https://tools.ietf.org/html/draft-irtf-icnrg-icnlowpan-04
[2] https://tools.ietf.org/html/draft-mosko-icnrg-ccnxchunking-02
[3] https://tools.ietf.org/html/draft-mosko-icnrg-ccnxserialversion-00
[4] https://redmine.named-data.net/projects/ndn-tlv/wiki/NameComponentType

--
Cenk Gündoğan

Hamburg University of Applied Sciences
Dept. of Computer Science / Internet Technologies Group
Berliner Tor 7, 20099 Hamburg, Germany
Fon: +49 40 42875 - 8426
Mail: cenk.guendogan@haw-hamburg.de
Web: https://www.inet.haw-hamburg.de/