Subject: Re: [mpls] draft-ietf-mpls-lsp-ping-ospfv3-codepoint-04.txt

From: tom petch <[email-masked]>
Date: Tue, 2 Feb 2021 17:39:36 +0000

I believe that this I-D needs a Normative Reference to
             Updating the IANA MPLS LSP Ping Parameters
             draft-ietf-mpls-lsp-ping-registries-update
since that I-D updates the registry that this I-D then seeks to update and if this I-D gets there first then the update can be overridden by
             Updating the IANA MPLS LSP Ping Parameters
             draft-ietf-mpls-lsp-ping-registries-update-07
and lost.

And this last I-D changes the meaning of the registry which could be seen as theoretically rendering this I-D invalid.

Tom Petch

From: mpls <[email-masked]> on behalf of [email-masked] <[email-masked]>
Sent: 27 January 2021 20:58

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Multiprotocol Label Switching WG of the IETF.

        Title           : OSPFv3 CodePoint for MPLS LSP Ping
        Authors         : Nagendra Kumar Nainar
                          Carlos Pignataro
                          Mustapha Aissaoui
        Filename        : draft-ietf-mpls-lsp-ping-ospfv3-codepoint-04.txt
        Pages           : 6
        Date            : 2021-01-27

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From: Loa Andersson <[email-masked]>
Date: Wed, 3 Feb 2021 13:05:24 +0800

Tom,

While I'm a great fan of references, I don't see that it is necessary in 
this case.

draft-ietf-mpls-lsp-ping-registries-update updates the Message Types, 
Reply Modes, Return Codes. TLV and sub-TLV registries.

The code point for draft-ietf-mpls-lsp-ping-ospfv3-codepoint is 
allocated from the "Protocol in the Segment ID sub-TLV" registry. This 
registry is not change, so I don't see that the scenario you describe 
below could play out.

/Loa

-- 

Loa Andersson                        email: [email-masked]
Senior MPLS Expert                          [email-masked]
Bronze Dragon Consulting             phone: +46 739 81 21 64

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From: tom petch <[email-masked]>
Date: Wed, 3 Feb 2021 09:38:28 +0000

From: Loa Andersson <[email-masked]>
Sent: 03 February 2021 05:05

Tom,

<tp>
My starting point is that I cannot make sense of the IANA Considerations in this I-D. They might be clearer if they used the allocated numbers for TLV and sub-TLV.  

It  says
"   IANA is requested to assign a new code point for OSPFv3 from
   "Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV"
   registry under the "Multi-Protocol Label Switching (MPLS) Label
   Switched Paths (LSPs) Ping Parameters" registry as follows:"

Downstream Detailed Mapping TLV would appear to be TLV20 so Protocol in Label Stack Sub-TLV should be a sub-TLV of TLV20; there is no such sub-TLV. IANA lists
1 Multipath data [RFC8029]  
2 Label stack [RFC8029]  
3 FEC stack change [RFC8029]  
4 Local Interface Index [RFC8611]  
5 Remote Interface Index [RFC8611]  

I find that problematic.

Tom Petch 

/Loa

--

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From: Loa Andersson <[email-masked]>
Date: Thu, 4 Feb 2021 15:12:57 +0800

Tom,

Are you strting to understand why I spent time to clean up the LSP Ping 
registry :) ??

I'm convinced that by the updates ine 
draft-ietf-mpls-lsp-ping-registries-update erything in this registry is 
cöose to coorect.

Howeve it is not always clear and it is easy to go wrong.

Let us see if I can sort it out (and if you have text for improvements 
that is fine)

LDP Ping has two messages "Echo Request" and "Echo Reply".
- both message may carry a "Downstream Detailed Mapping TLV"

-- the Downstream Detailed Mapping TLV has a "Labels Stack sub-TLV"

--- Labels Stack sub-TL has a "Protocol" code point (see registry
     "Protocol in Label Stack Sub-TLV of Downstream Detailed
      Mapping TLV".

---- it is Protocol code point registry that is updated and extended by
      the draft-ietf-mpls-lsp-ping-ospfv3-codepoint

Similarly the "Echo Request" and "Echo Reply"
  has three TLVs
-Type 1 (Target FEC Stack)
  Type 16 (Reverse Path - Target FEC Stack)
  Type 21 (Reply Path)

-- Each of these TLVs has three sub-TLVs has a Segment ID sub-TLV

--- Segment ID su-b-TLV has a "Protocol" code point

---- it is Protocol code point registry that is updated and extended by
      the draft-ietf-mpls-lsp-ping-ospfv3-codepoint

The protocol registgries are not update by 
draft-ietf-mpls-lsp-ping-registries-update.

/Loa

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