Re: [Dots] DOTS telemetry questions

["Jon Shallow" <[e-mail]>]

Hi Med et al,

 

See inline Jon>

 

Regards

 

Jon

 

From: Dots [mailto: [e-mail]] On Behalf Of
[e-mail]
Sent: 21 February 2020 07:00
To: Jon Shallow; Konda, Tirumaleswar Reddy; kaname nishizuka
Cc: [e-mail]
Subject: Re: [Dots] DOTS telemetry questions

 

Hi Jon,

 

(ccing the WG to track the changes).

 

Please see inline.

 

Cheers,

Med

 

De : Jon Shallow [mailto:[e-mail]] 
Envoyé : jeudi 20 février 2020 21:58
À : BOUCADAIR Mohamed TGI/OLN; Konda, Tirumaleswar Reddy; kaname nishizuka
Objet : DOTS telemetry questions

 

Hi Guys,

 

1)      For example CBOR mappings

 

     Header: PUT (Code=0.03)

     Uri-Path: ".well-known"

     Uri-Path: "dots"

     Uri-Path: "mitigate"

     Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"

     Uri-Path: "mid=123"

     If-Match:

     Content-Format: "application/dots+cbor"

 

     {

      "ietf-dots-signal-channel:mitigation-scope": {

        "scope": [

          {

            "alias-name": [

               "myserver"

             ],

            "attack-status": "under-attack",

            "ietf-dots-telemetry:total-attack-traffic": [

              {

                "ietf-dots-telemetry:unit": "megabytes-ps",

                "ietf-dots-telemetry:mid-percentile-g": "900"

              }

            ]

          }

        ]

      }

     }

 

    Figure 33: An Example of Mitigation Efficacy Update with Telemetry

                                Attributes

 

And yet the mapping table only has (no ietf-dots-telemetry: prefix)

 

    | total-attack-traffic | list        |32794 | 4 array       | Array  |

 

I appreciate that ietf-dots-telemetry:total-attack-traffic and total-attack
traffic are the same CBOR value (or are they?)

[Med] The same value is used but I didn’t check if there are side effects. 

Jon> Need to think this through.  My implementation maps the CBOR into JSON
and then works on the JSON to do what is necessary and then converts the
JSON response back into CBOR.

Jon> We  have the same naming issues in
draft-ietf-dots-signal-filter-control-00 where we do not have the
ietf-dots-signal-control: prefix in the JSON examples (Fig 10)

 

Please note that we have this note is section 10:

 

==

   o  Some of these attributes should be prepended with "ietf-dots-

      telemetry:"

==

 

but when mapping the CBOR back to JSON the variant of JSON parameter is
context (Uri-Path: mitigate or tm) dependent.

 
2)      why do we not have a “enum megabit-ps” in “typedef unit” in the YANG
Module?
[Med]  This can be added to the list as ‘units()’ are negotiated. *-bytes
are more used for aggregates, but let’s be consistent and have both
bit/bytes in the units.
Jon> Megabytes works with aggregates, megabits works with pipes.
  
 
3)      I think that I have worked out that server-originated-telemetry if
set allows telemetry included in the mitigation status rather than only
returned using Uri-path: tm – correct?
[Med] I confirm. Note that including pre-mitigation returned using
“Uri-path:tm” is controlled by PUT/GET (Section 7.3).
Jon> Agreed.  

 

4)      I am confused by “pre-mitigation” which can be transmitted pre any
mitigation taking place, or actually during when mitigation is taking place
(or so I think) and would simply be better described as “attack-details” –
especially with a statement such as

 

   DOTS agents MUST bind pre-mitigation telemetry data with mitigation
   requests relying upon the target clause.
 
[Med] That’s an option but the current design allows to have the telemetry
in // in order to supply more data ** without impacting the placement of a
mitigation request ** hence the need to bind both (if any). If telemetry
attributes are defined as mandatory (discussed in another thread), this
would mean that the server will reject a mitigation that includes such
attributes. With the current design, we have a functionality that can be
safely enabled independently of the decision that we will make about whether
telemetry attributes are mandatory to be supported or not.
Jon> My primary point here was the use of the term “pre-mitigation” – this
telemetry is also needs during a mitigation and the attack keeps on morphing
into something else.
 
Another point we can check to ease correlation between a mitigation request
and pre-mitigation telemetry is to signal the “mid” in the telemetry
message.
Jon> could be – need to think this through
 
Regards
 
Jon