Re: [Dots] New Version Notification for draft-moskowitz-dots-ssls-02.txt

On 21-Mar-2016 11:43 am, Robert Moskowitz <rgm-sec@htt-consult.com> wrote: 
> For my agenda item on 
> 
> Introducing session layer considerations
> 
> Please see the following draft.  There are a number of 'embedded' drafts to work through to get the whole story.  I will start a discuss on this tomorrow on the list.

If we need fragmentation support, a fragmentation layer on top of DTLS would serve us better than SSLS.  DTLS already handles fragmentation for its own handshakes (similar to IKE's RFC7383), leaving us with solving the fragmentation/reassembly. I see both draft-fossati-dtls-over-gsm-sms (expired) and draft-hartke-dice-practical-issues (expired) explored the problem and some solutions with small-MTU networks with UDP packets.

But back to requirements for a moment:  what is the minimum MTU we need DOTS signaling to be sent over?  I have always imagined we are running over the same network as the Internet-originated DoS traffic itself is originated from the Internet or from a WiFi, LTE, or Ethernet-connected device, which means the MTU is approximately 1280 bytes (considering both IPv6 minimum MTU of 1280, and the typical IPv4 MTU seen on the Internet).  But it seems draft-moskowitz-dots-ssls is anticipating using SMS for signaling.  According to draft-fossati-dtls-over-gsm-sms, SMS can do its own reassembly ("Concatenated short messages") so for SMS it seems we (IETF) don't need to do protocol work SMS fragmentation/reassembly.

-d

> 
> 
> 
> -------- Forwarded Message --------
> Subject:	New Version Notification for draft-moskowitz-dots-ssls-02.txt
> Date:	Mon, 21 Mar 2016 11:40:20 -0700
> From:	internet-drafts@ietf.org <mailto:internet-drafts@ietf.org>
> To:	Robert Moskowitz <rgm@labs.htt-consult.com> <mailto:rgm@labs.htt-consult.com>, Susan Hares <shares@ndzh.com> <mailto:shares@ndzh.com>
> 
> A new version of I-D, draft-moskowitz-dots-ssls-02.txt
> has been successfully submitted by Robert Moskowitz and posted to the
> IETF repository.
> 
> Name:		draft-moskowitz-dots-ssls
> Revision:	02
> Title:		DOTS Secure Session Layer Services
> Document date:	2016-03-21
> Group:		Individual Submission
> Pages:		6
> URL:            https://www.ietf.org/internet-drafts/draft-moskowitz-dots-ssls-02.txt <https://www.ietf.org/internet-drafts/draft-moskowitz-dots-ssls-02.txt>
> Status:         https://datatracker.ietf.org/doc/draft-moskowitz-dots-ssls/ <https://datatracker.ietf.org/doc/draft-moskowitz-dots-ssls/>
> Htmlized:       https://tools.ietf.org/html/draft-moskowitz-dots-ssls-02 <https://tools.ietf.org/html/draft-moskowitz-dots-ssls-02>
> Diff:           https://www.ietf.org/rfcdiff?url2=draft-moskowitz-dots-ssls-02 <https://www.ietf.org/rfcdiff?url2=draft-moskowitz-dots-ssls-02>
> 
> Abstract:
>    This document describes using a session layer service for DOTS
>    messaging to provide secure messaging while delivering on a number of
>    DOTS requirements including avoiding fate-sharing with the under-
>    lying communications.
> 
>                                                                                   
> 
> 
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at tools.ietf.org.
> 
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