Given that they are responding to customers “Working as designed” and pointing 
to those RFCs as the reason, yes, I think enabling customers to point back at 
the RFCs and say “You got it wrong and the
RFC now says so” will actually help.

Owen


> On Sep 18, 2023, at 09:07, Robert Raszuk <[email protected]> wrote:
> 
> 
> Looks like this problem is known for over 13 years - Looks like a day one 
> implementation bug: 
> 
> https://juniper-nsp.puck.nether.narkive.com/2DmYT8s6/j-nsp-ospfv3-junos-sends-zero-mtu-in-dbd-stuck-in-exstart
> 
> Do you think fixing a few RFCs which are pretty obvious what the behaviour 
> should be will really help ? 
> 
> Cheers,
> R.
> 
> 
> 
> 
> On Mon, Sep 18, 2023 at 5:46 PM Owen DeLong <[email protected] 
> <mailto:[email protected]>> wrote:
>> Happy to achieve the desired result (clarification) through whatever is the 
>> best mechanism, whether that be reattached, addition of a terminology 
>> section, or some other process not yet expressed.
>> 
>> The vendor I referred to as getting this wrong is a very large router 
>> vendor. Multiple parties that have reported this issue through their TAC 
>> have been told “working as designed” with reference to this section and to 
>> section A.3.3 of RFC 5343 (for which I have submitted a similar errata 
>> report (7645). 
>> 
>> I’m trying to do this without public shaming of the vendor in question, but 
>> they are one of the domains in the CC list of this message. 
>> 
>> As such, I don’t think this mistake is limited to casual readers. 
>> 
>> Owen
>> 
>> 
>>> On Sep 18, 2023, at 05:13, Acee Lindem <[email protected] 
>>> <mailto:[email protected]>> wrote:
>>> 
>>> Hi Robert, 
>>> 
>>> 
>>> 
>>>> On Sep 18, 2023, at 07:50, Robert Raszuk <[email protected] 
>>>> <mailto:[email protected]>> wrote:
>>>> 
>>>> Acee,
>>>> 
>>>> I agree with your assessment. 
>>>> 
>>>> But looking at the RFC I would say it is missing a Terminology section. If 
>>>> such section would clearly define meaning of virtual link in the context 
>>>> of this RFC there would be no ambiguity. 
>>>> 
>>>> Otherwise those not skilled in OSPF art may take a document and apply 
>>>> casual meaning to virtual link (which does indeed include a tunnel of any 
>>>> sort :). 
>>>> 
>>>> Of course this entire RFC is about OSPFv3 so this should be very intuitive 
>>>> to read it in such context not as casual IETF issued paper. 
>>> 
>>> Right. 
>>> 
>>>> 
>>>> If any errara is needed here IMHO is just to add terminology section 
>>>> unless there is some formal definition that in all IETF RFCs terms apply 
>>>> only to the context of given subject doc. I am honestly not sure if there 
>>>> is one. 
>>> 
>>> I believe you could take almost any Routing RFC and improve it with editing 
>>> and the addition of more context. This was clearly the case for 
>>> https://datatracker.ietf.org/doc/draft-ietf-rtgwg-vrrp-rfc5798bis/
>>> 
>>> This started out as a respin of the document for inclusive language but I 
>>> also made significant edits to improve the readability (as well as address 
>>> errata and other minor errors). After that, I received some really good 
>>> input from reviewers (e.g., Quentin Arimitage provided around 70 comments 
>>> and suggestions, most of which were incorporated). 
>>> 
>>> However, improvements such as these are usually not done with an Errata. 
>>> 
>>> Thanks,
>>> Acee
>>> 
>>> 
>>> 
>>>> 
>>>> Thx,
>>>> R.
>>>> 
>>>> On Mon, Sep 18, 2023 at 1:27 PM Acee Lindem <[email protected] 
>>>> <mailto:[email protected]>> wrote:
>>>>> 
>>>>> 
>>>>> > On Sep 17, 2023, at 22:07, Owen DeLong <[email protected] 
>>>>> > <mailto:[email protected]>> wrote:
>>>>> > 
>>>>> > You say they are unnecessary, then why do we have vendors doing this 
>>>>> > wrong and pointing to this requirement of the RFC as their reason for 
>>>>> > doing so?
>>>>> > 
>>>>> > While there may be a valid argument that they shouldn’t be necessary, I 
>>>>> > would argue that real world implementation experience suggests that 
>>>>> > they are
>>>>> > most definitely necessary and are a minor edit to provide additional 
>>>>> > clarity.
>>>>> 
>>>>> An OSPF virtual link and a tunnel (e.g., GRE tunnel) are totally 
>>>>> different constructs. The vendor is incorrect in arguing that this text 
>>>>> specifics operation over a GRE tunnel. Rather, they should be arguing 
>>>>> that OSPF doesn’t have any path MTU capabilities and since a tunnel can 
>>>>> be multi-hop, OSPF doesn’t know the MTU. 
>>>>> 
>>>>> Thanks,
>>>>> Acee
>>>>> 
>>>>> 
>>>>> > 
>>>>> > Are you really arguing to preserve ambiguous language when the problem 
>>>>> > is so easy to solve?
>>>>> > 
>>>>> > Owen
>>>>> > 
>>>>> > 
>>>>> > 
>>>>> >> On Sep 17, 2023, at 15:25, Acee Lindem <[email protected] 
>>>>> >> <mailto:[email protected]>> wrote:
>>>>> >> 
>>>>> >> Given that the context of the “Interface MTU” is specifically the 
>>>>> >> “interface MTU” field in OSPFv3 Database Description packets and OSPF 
>>>>> >> virtual links (RFC 2328), the additions recommended in this Errata are 
>>>>> >> unnecessary. The Errata should be rejected. 
>>>>> >> 
>>>>> >> Thanks,
>>>>> >> Acee
>>>>> >>> On Sep 17, 2023, at 15:58, RFC Errata System 
>>>>> >>> <[email protected] <mailto:[email protected]>> wrote:
>>>>> >>> 
>>>>> >>> The following errata report has been submitted for RFC5838,
>>>>> >>> "Support of Address Families in OSPFv3".
>>>>> >>> 
>>>>> >>> --------------------------------------
>>>>> >>> You may review the report below and at:
>>>>> >>> https://www.rfc-editor.org/errata/eid7644
>>>>> >>> 
>>>>> >>> --------------------------------------
>>>>> >>> Type: Technical
>>>>> >>> Reported by: Owen DeLong <[email protected] <mailto:[email protected]>>
>>>>> >>> 
>>>>> >>> Section: 2.7
>>>>> >>> 
>>>>> >>> Original Text
>>>>> >>> -------------
>>>>> >>> Interface MTU
>>>>> >>>    The size in octets of the largest address family specific datagram
>>>>> >>>    that can be sent on the associated interface without
>>>>> >>>    fragmentation.  The MTUs of common Internet link types can be
>>>>> >>>    found in Table 7-1 of [MTUDISC].  The Interface MTU SHOULD be set
>>>>> >>>    to 0 in Database Description packets sent over virtual links.
>>>>> >>> 
>>>>> >>> 
>>>>> >>> Corrected Text
>>>>> >>> --------------
>>>>> >>> Interface MTU
>>>>> >>>    The size in octets of the largest address family specific datagram
>>>>> >>>    that can be sent on the associated interface without
>>>>> >>>    fragmentation.  The MTUs of common Internet link types can be
>>>>> >>>    found in Table 7-1 of [MTUDISC].  The Interface MTU SHOULD be set
>>>>> >>>    to 0 in Database Description packets sent over (OSPF3) virtual 
>>>>> >>> links.
>>>>> >>>    This recommendation MUST NOT be applied to tunnel and other virtual
>>>>> >>>    or software interfaces which carry traffic other than OSPF 
>>>>> >>> protocol packets.
>>>>> >>> 
>>>>> >>> Notes
>>>>> >>> -----
>>>>> >>> Currently, the language is ambiguous and at least one vendor has 
>>>>> >>> implemented OSPF3 sending an MTU of zero on GRE interfaces (and 
>>>>> >>> possibly others such as IPIP, IPSEC, etc., as I have not tested 
>>>>> >>> these). I believe that the intent of the RFC is to refer strictly to 
>>>>> >>> OSPF virtual-links which carry only OSPF protocol data and therefore 
>>>>> >>> have no meaningful MTU. When this is mistakenly applied to other 
>>>>> >>> forms of "virtual" interfaces such as tunnels, the results can be 
>>>>> >>> quite harmful.
>>>>> >>> 
>>>>> >>> As such, I think that clarification is in order, since the vendor in 
>>>>> >>> question is unrepentant and claims their current implementation to be 
>>>>> >>> compliant with the RFC.
>>>>> >>> 
>>>>> >>> Instructions:
>>>>> >>> -------------
>>>>> >>> This erratum is currently posted as "Reported". If necessary, please
>>>>> >>> use "Reply All" to discuss whether it should be verified or
>>>>> >>> rejected. When a decision is reached, the verifying party  
>>>>> >>> can log in to change the status and edit the report, if necessary. 
>>>>> >>> 
>>>>> >>> --------------------------------------
>>>>> >>> RFC5838 (draft-ietf-ospf-af-alt-10)
>>>>> >>> --------------------------------------
>>>>> >>> Title               : Support of Address Families in OSPFv3
>>>>> >>> Publication Date    : April 2010
>>>>> >>> Author(s)           : A. Lindem, Ed., S. Mirtorabi, A. Roy, M. 
>>>>> >>> Barnes, R. Aggarwal
>>>>> >>> Category            : PROPOSED STANDARD
>>>>> >>> Source              : Open Shortest Path First IGP
>>>>> >>> Area                : Routing
>>>>> >>> Stream              : IETF
>>>>> >>> Verifying Party     : IESG
>>>>> >>> 
>>>>> >>> _______________________________________________
>>>>> >>> Lsr mailing list
>>>>> >>> [email protected] <mailto:[email protected]>
>>>>> >>> https://www.ietf.org/mailman/listinfo/lsr
>>>>> >> 
>>>>> > 
>>>>> 
>>>>> _______________________________________________
>>>>> Lsr mailing list
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>>> 

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