Based on the IESG expert’s review, some unsolved issues are emerging again.

Top post two points of Eric’s review and Peter’s response, and I would like to 
hear the IESG expert’s opinions(also the author’s explanations):

 

1)    ### Section 2

There are two "SHOULD" in this section but nothing is written the cases when
these "SHOULD" can be bypassed and/or what are the consequences.

##PP

I added:

"Not withdrawing the UPA would result in stale information being kept in the 
link state database of all 
routers in the area."

[WAJ] How to “withdrawing the UPA” ? There is no EXPLICIT UPA withdraw message.

Does “Stop advertising the UPA”  equal to “withdrawing the UPA”?

 

2)    ### Section 3.1

`Those ABRs or ASBRs, which are responsible for propagating UPA advertisements
into other areas or domains MUST also recognize UPA advertisements.` what are
the consequences if this is not the case (e.g., not all ABR/ASBR have been
upgraded). Should this be mentioned in an operational considerations section ?

##PP
added:

"Failure to do so would prevent UPA to reach the routers in the remote areas or 
domains."

[WAJ] I think Eric raised one interesting question. Such question actually 
relate to the network partition scenario, which this draft try to avoid.

The added sentence can’t be implemented-----Image there are two ABRs, and one 
ABR(ABR A) can recognize the UPA advertisements, another ABR(ABR B) can’t.

How can ABR B(which is not upgraded) “prevent UPA to reach the routers in the 
remote areas or domains” (ABR A has already send out the UPA advertisements)

 

3)    There are also other unsolved issues in this document, which I have 
responses to the IETF chair at 
https://mailarchive.ietf.org/arch/msg/lsr/drZyz2YIucydqXImG05C75APDZU/ 
(especially item 1)

I wonder that are there any expert can response/consider carefully the existing 
issues, which will stop the mechanism work in the network.

 

Best Regards

 

Aijun Wang

China Telecom

 

From: [email protected] [mailto:[email protected]] On 
Behalf Of Peter Psenak
Sent: Thursday, September 18, 2025 5:57 PM
To: Éric Vyncke <[email protected]>; The IESG <[email protected]>
Cc: [email protected]; [email protected]; 
[email protected]; [email protected]
Subject: [Lsr] Re: Éric Vyncke's No Objection on 
draft-ietf-lsr-igp-ureach-prefix-announce-09: (with COMMENT)

 

Hi Eric,

 

thanks for your comments, please see my responses inline (##PP):

 

 

On 17/09/2025 17:35, Éric Vyncke via Datatracker wrote:

Éric Vyncke has entered the following ballot position for
draft-ietf-lsr-igp-ureach-prefix-announce-09: No Objection
 
When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)
 
 
Please refer to 
https://www.ietf.org/about/groups/iesg/statements/handling-ballot-positions/ 
for more information about how to handle DISCUSS and COMMENT positions.
 
 
The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-lsr-igp-ureach-prefix-announce/
 
 
 
----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------
 
 
# Éric Vyncke, INT AD, comments for draft-ietf-lsr-igp-ureach-prefix-announce-09
CC @evyncke
 
Thank you for the work put into this document.
 
Please find below some non-blocking COMMENT points/nits (replies would be
appreciated even if only for my own education).
 
Special thanks to Yingzhen Qu for the shepherd's detailed write-up including
the WG consensus (important to note for this I-D) _but it lacks_ the
justification of the intended status.
 
I hope that this review helps to improve the document,
 
Regards,
 
-éric
 
## COMMENTS (non-blocking)
 
### Title
 
s/IGP Unreachable Prefix Announcement/Unreachable Prefix *IGP* Announcement/
sounds clearer to me but English is not my primary language.

##PP
I let the RFC Editors to decide, I feel what we have is better.

 
 
### Abstract
 
s/This document describes/This document *specifies*/ as this is proposed
standard.

##PP
done

 
 
### Section 1
 
Who is the "we" in `we want to signal unreachability` ? The authors ? The LSR
WG ? The IETF ? Please avoid using ambiguous "we" by rephrasing the sentence.

##PP
done

 
 
s/ISIS/IS-IS/ ? and in other places.

##PP
done 

 
 
### Section 2
 
s/for a prefix that is summarized by the summary *address*/for a prefix that is
summarized by the summary *prefix*/ ?

##PP
done 

 
 
There are two "SHOULD" in this section but nothing is written the cases when
these "SHOULD" can be bypassed and/or what are the consequences.

##PP

I added:

"Not withdrawing the UPA would result in stale information being kept in the 
link state database of all 
routers in the area."

 
 
Add "and OSPFv3" at the end of `so the above optimisation does not apply to
OSPF` ? It seems that the I-D sometimes uses OSPF for OSPFv2 alone and
sometimes for OSPFv2 and OSPFv3.

##PP
I added and OSPFv3 at the end of the sentence,

 
 
### Section 3.1
 
Add "to support this specification" after `without the need to upgrade all
nodes in a network.` ?

##PP
done

 
 
`Those ABRs or ASBRs, which are responsible for propagating UPA advertisements
into other areas or domains MUST also recognize UPA advertisements.` what are
the consequences if this is not the case (e.g., not all ABR/ASBR have been
upgraded). Should this be mentioned in an operational considerations section ?

##PP
added:

"Failure to do so would prevent UPA to reach the routers in the remote areas or 
domains."

 
 
### Section 5.1
 
Was the use of a 2-bit field considered rather than using 2 flags ? It would
have allowed 4 values as opposed as the current 3 values. Out of curiosity
because it is probably too late to change it...

##PP
RFC7444 defines the "IPv4/IPv6 Extended Reachability Attribute Flags" TLV, 
which is a variable length bitfield. We are simply adding two new bits in that 
bitfield.

 

 
 
### Section 8
 
It is often preferable to add an informational reference to the URI of the
registries.

#PP
never done it, can you please provide an example RFC/draft, I'll follow that.

thanks,
Peter

 

 
 
 
 
 

 

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