Re: [bess] Éric Vyncke's Discuss on draft-ietf-bess-evpn-igmp-mld-proxy-13: (with DISCUSS and COMMENT)

["Mankamana Mishra (mankamis)" <[e-mail]>]

Hi Eric,
Thanks for comment. Please find inline comment for blocking disucss .

Mankamana

From: Éric Vyncke via Datatracker <[e-mail]>
Date: Wednesday, October 20, 2021 at 1:28 AM
To: The IESG <[e-mail]>
Cc: [e-mail] <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Subject: Éric Vyncke's Discuss on draft-ietf-bess-evpn-igmp-mld-proxy-13: (with DISCUSS and COMMENT)
Éric Vyncke has entered the following ballot position for
draft-ietf-bess-evpn-igmp-mld-proxy-13: Discuss

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DISCUSS:
----------------------------------------------------------------------

Thank you for the work put into this document. I have to state that I am
neither a EVPN expert not a multicast one.

Please find below some blocking DISCUSS points (probably easy to address), some
non-blocking COMMENT points (but replies would be appreciated even if only for
my own education), and some nits.

Special thanks to Stéphane Litkowski for his shepherd's write-up about the WG
consensus.

I hope that this helps to improve the document,

Regards,

-éric

== DISCUSS ==

The text covers in details how to map MLD/IGMP into BGP routes but does not say
a word on how to recreate the MLD/IGMP packets. Should there be any such
specification ?
Mankamana :  This draft covers what is EVPN related procedures. IGMP / MLD packets are generated by multicast host. And this document does not define any procedure about what needs to be done at host. Host is not even aware of presense of EVPN


Are all multicast group address treated as the same ? I would have appreciated
some text about link-local multicast as well as global multicast groups
addresses.
Mankamana : Since this draft transport all Valid IGMP / MLD join over BGP. It does not differentiate between different group range. All verification and handeling would be still IGMP / MLD router responsibility, so I do not think we would need to mention any of this.


-- Abstract --
While this point is pretty light for a blocking DISCUSS, let's fix it:
- the abstract should also mention MLD and not only IGMP
- what are 'the above services' ?

-- Section 1 --
In the same vein, is it about IGMP only ? Or does it include MLD as well ? It
is really unclear.

Mankamana : Added MLD in abstract. But later in terminology, it has been mentioned that even though we have used term IGMP, its valid for MLD too. For better redability, MLD has been not used in rest of document.


----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

A very generic comment (but no need to reply): how can an IETF draft still
prefers to use "IGMP" rather than "MLD" in the text in 2021 ? ...

-- Section 1 --
When reading this section, I really and genuinely wonder what is "distributed
anycast multicast router" ? AFAIK "any cast" and "multicast" addresses are
vastly different.

Anycast multicast is well known , and do not think there is need to mention it more in document about it.

-- Section 3 --
Is there any reason why the terminology is not alphabetically sorted ?

Please also add 'BD'.

Usually a terminology section is not only about acronym expansions but also
about definitions.
Done


-- Section 4.1 --
What is the definition of a 'first hop PE'? What is the difference with a EVPN
PE ?

EVPN PE  is PE were EVPN is enabled. Not adding detail for some of obvious terminology.

-- Section 4.2 --
May be that I overlooked it, but what is a 'proxy querier' ?
IGMP spec defines need for Querier on LAN. EVPN provides mechanism to extend layer-2 network across core.  And this draft defines mechanism to convert these local IGMP / MLD join to BGP routes and send it across core. Each of these location should have own Querier configured and refresh joins on behalf of other sites.


What is the difference between "EVPN core" and "MPLS/IP core" ?
EVPN core is generic term, it could be SR / SRv6 / MPLS or IP underlay based.


-- Section 5.1 --
What is "viz" ? (Sorry not being a native English speaker)


viz introduce examples or further details to illustrate a point

-- Section 8 --
Is there a difference between (*, G) and (x, G) ?
(x,G) is generic term to denote both (S,G) and (*,G).
-- Section 9.1 --
Please formally specify "IE" as "include/exclude" (if not mistaken).
done

I find the description of the bits for MLD confusing, it really appears as a
last-minute add-on to the text. Why not describing the MLDv1 in the same bullet
as in IGMPv1 for the bit 7 ?
IGMP and MLD have historically version number mismatch. So we added it independently to avoid confusion. IGMP has V1, V2, V3 and MLD has only V1 and V2. And for mapping
  IGMP V1
  IGMP V2 ---- MLD V2
 IGMP V3 – MLD V3
So I think keeping it independent would be better.

Is "SHOULD" the right word for the sender of the reserved bits ? Especially as
section 9.1.1. specifies a "MUST".

Changed

-- Sections 9.1, 9.2 --
The flags description appears to be different in the text while it seems to me
that they have the same semantics.

9.2 adds little more text , may not no change needed.

== NITS ==

Is it "ToR" or "TOR" ?

ToR

-- Section 4.1.2 --
Please use a consistent quoting in the document, e.g. in :
        IGMPv2 Leave Group (Leave) or IGMPv3 "Leave"

Removed extra leave for V2