Subject: [Anima] grasp-dnssd and services-dns-autoconfig [was ANIMA IETF113 notes posted]

From: Brian E Carpenter <[email-masked]>
Date: Sat, 9 Apr 2022 14:45:20 +1200

> DNS-SD Compatible Service Discovery in GRASP
> 
> Presenter: Toerless Eckert
> Time: 5 minutes
> Draft: https://datatracker.ietf.org/doc/draft-eckert-anima-grasp-dnssd/03/ (was -02 at IETF112)
> 
> The document is quite stable and any review is appreciated.

> 10 Autoconfiguration of infrastructure services in ACP networks via DNS-SD over GRASP
> 
> Presenter: Toerless Eckert
> Time: 5 minutes
> Draft: https://datatracker.ietf.org/doc/draft-eckert-anima-services-dns-autoconfig/01/ (was -01 at IETF112)
> 

> 
> Toerless askes for WG adoption of both drafts.

I haven't re-reviewed these recently but I did study them quite a while ago
and verified (by implementing it) that the GRASP/DNSSD interface works
quite well. I agree with Sheng's comment that more review is needed, but
I think that needs to come from a practising netops specialist. Is what
the drafts describe realistic in practice? I don't really know.

fwiw my code sits at
https://github.com/becarpenter/graspy/blob/master/AskDNSSD2.py
https://github.com/becarpenter/graspy/blob/master/GetDNSSD2.py

Regards
    Brian

---

From: Toerless Eckert <[email-masked]>
Date: Sat, 9 Apr 2022 19:37:38 +0200

> the drafts describe realistic in practice? I don't really know.

The services autoconfig functionality described was modelled pretty much
after the same functionality in the pre-standard ACP implementation
in Cisco IOS except that Cisco IOS ACP uses multihop mDNS forwarding.
without those services or experience in that implementation has been that
it is not possible to achieve zero touch rfc8366, aka: using the ACP with
existing networks to enable remote CLI/SDN configurability. Instead it is
exactly whats described in these drafts whats missing (vs. what we already
standardized in ANIMA). That pre-standard implementation functionality
was also valided by several customers and is publically documented.

The main difference  is therefore really the replacement of mDNS encoding/transport
of the service announcements with GRASP encoding/transport and we heard from 
Stuart Cheshire that he agrees and supports our approach from the drafts.

Aka: i think we do have the netops experience.

> https://github.com/becarpenter/graspy/blob/master/GetDNSSD2.py

Thanks!

Cheers
    Toerless

-- 
---
[email-masked]

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From: Brian E Carpenter <[email-masked]>
Date: Mon, 11 Apr 2022 15:54:27 +1200

> Aka: i think we do have the netops experience.

Understood, but wouldn't we be happier with a review by a third party?
If nobody in anima is willing, maybe ask ops-dir to help?

    Brian

---

From: Michael Richardson <[email-masked]>
Date: Mon, 11 Apr 2022 12:44:48 -0400

Toerless Eckert <[email-masked]> wrote:
    > The main difference is therefore really the replacement of mDNS
    > encoding/transport of the service announcements with GRASP
    > encoding/transport and we heard from Stuart Cheshire that he agrees and
    > supports our approach from the drafts.

I think that maybe the fact that this is a *re-encoding* of mDNS into
GRASP(CBOR) needs more emphasis.

I don't have a specific text suggestion as yet.

That this is not a replacement of mDNS by GRASP, or a replacement of GRASP
with mDNS is something I keep forgetting when I encounter the documents
again after being away from them for a few weeks.

-- 
Michael Richardson <[email-masked]>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide

---

From: Brian E Carpenter <[email-masked]>
Date: Tue, 12 Apr 2022 08:49:35 +1200

> GRASP(CBOR) needs more emphasis.

Yes, you're right. I hadn't thought of it exactly like that, but it
explains why my demo ASA is called AskDNS. All it does is a fancy DNS
lookup, proxied via GRASP, with the result delivered in a JSON-like
map. The fact that it's intended for mDNS is almost irrelevant.
It means that you don't need DNS client software in the client,
which should be a win if you already have GRASP.

     Brian