Re: [Dots] WGLC on draft-ietf-dots-signal-call-home-06

"Jon Shallow" <> Wed, 06 November 2019 17:12 UTC

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From: "Jon Shallow" <>
To: "'Valery Smyslov'" <>, <>, <>
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Date: Wed, 6 Nov 2019 17:12:34 -0000
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Subject: Re: [Dots] WGLC on draft-ietf-dots-signal-call-home-06
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Hi All,

I have done a preliminary working implementation of DOTS Call-Home  - there
is still some little used functionality to finish off.

*** Issue # 1 - TCP TLS sessions

" If UDP transport is used, the Call Home DOTS server begins by
initiating a DTLS connection to the Call Home DOTS client."

This works as expected where the UDP + DTLS layer roles are switched.

" If TCP is used, the Call Home DOTS server begins by initiating a
TCP connection to the Call Home DOTS client.  Using this TCP
connection, the Call Home DOTS server initiates a TLS connection
to the Call Home DOTS client."

With the current libcoap implementation, I am unable to create a CoAP
session using TLS on an existing TCP connection - so the DOTS Client is
unable to accept an incoming TCP session and then initiate TLS integrated
with the CoAP session.  I agree that RFC8071 only switches the TCP layer
roles.  However all works if the TCP + TLS layer roles are switched - in the
same way that UDP + DTLS work.

Enhancing the libcoap code to support only the TCP layer being switched is
doable - but have no idea as to whether other CoAP implementations can
handle this specific requirement.

*** Not (yet) Implemented #1 - Redirected Signalling

I do not see any issues here.

*** Not (yet) implemented #2 - New Conflict Cause 4

I do not see any issues here.

*** Not (yet) Implemented #3 - Address sharing considerations

I do not see any issues here - just need to interface with the translators
to get the appropriate information.



> -----Original Message-----
> From: Dots [] On Behalf Of Valery
> Smyslov
> Sent: 23 October 2019 08:36
> To:
> Cc:
> Subject: [Dots] WGLC on draft-ietf-dots-signal-call-home-06
> Hi,
> this message starts a Work Group Last Call (WGLC) for
> call-home-06.
> The version to be reviewed is here:
> signal-call-home-06.txt
> The WGLC will last for two weeks and will end on November the 7th.
> Please send your comments to the list before this date.
> Regards,
> Frank & Valery.
> _______________________________________________
> Dots mailing list