Subject: Re: [Dots] [core] Large asynchronous notifications under DDoS: New BLOCK Option?

From: <[email-masked]>
Date: Fri, 29 May 2020 13:13:03 +0000

Hi all,

Please find below an update about this DOTS telemetry issue:

·         A proposal to handle the issue was made: https://tools.ietf.org/html/draft-bosh-core-new-block-00.

·         The core wg dedicated an interim meeting to discuss the proposal (May, 13).

o   The slides presented in the meeting ca be seen here: https://datatracker.ietf.org/meeting/interim-2020-core-04/materials/slides-interim-2020-core-04-sessa-new-coap-block-wise-transfer-options-draft-bosh-core-new-block.

o   The minutes can be seen at: https://datatracker.ietf.org/doc/minutes-interim-2020-core-04-202005131600/.

·         An updated version to address the comments received from the core wg (and especially during the interim) is available at: https://tools.ietf.org/html/draft-bosh-core-new-block-01.

·         The current plan is to avoid adding a normative dependency to the telemetry spec.

We will report back to the WG as appropriate.

Cheers,
Jon & Med

De : core [mailto:[email-masked]] De la part de [email-masked]
Envoyé : mardi 7 avril 2020 13:11
À : [email-masked]
Cc : Jon Shallow ([email-masked]); [email-masked]
Objet : [core] Large asynchronous notifications under DDoS: New BLOCK Option?

Hi all,

We are using Observe to receive notifications during attack events. These notifications are set as NON messages for reasons specific to DDoS conditions.

With DDoS telemetry information included (see draft-ietf-dots-telemetry), a notification may not fit one single message. The use of BLOCK2 is not convenient during attack times. A full description of the issue is described here: https://mailarchive.ietf.org/arch/msg/dots/Gbtf8bBWpxD9CWNBhS_TZtsWeP4/

We are considering some mechanisms to solve this issue. One of them is to define a new BLOCK option (similar to BLOCK2) that does not require the observer to send a GET to receive the next fragment. The server will send all the fragments. The observer will follow a SACK-like approach to request retransmission of missing fragments.

Please let us know whether you think this is a generic issue that should be solved at the CoAP or not. Suggestions are welcome.

Thank you.

Cheers,
Jon & Med