Re: Benoit Claise's Discuss on draft-ietf-6man-rfc1981bis-06: (with DISCUSS and COMMENT)

[Benoit Claise <[e-mail]>]

On 5/12/2017 5:26 AM, Fernando Gont wrote:
> On 05/11/2017 12:45 PM, Benoit Claise wrote:
>> Benoit Claise has entered the following ballot position for
>> draft-ietf-6man-rfc1981bis-06: Discuss
>>
>> 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/iesg/statement/discuss-criteria.html
>> for more information about IESG DISCUSS and COMMENT positions.
>>
>>
>> The document, along with other ballot positions, can be found here:
>> https://datatracker.ietf.org/doc/draft-ietf-6man-rfc1981bis/
>>
>>
>>
>> ----------------------------------------------------------------------
>> DISCUSS:
>> ----------------------------------------------------------------------
>>
>>    Nodes not implementing Path MTU Discovery MUST use the IPv6 minimum
>>     link MTU defined in [I-D.ietf-6man-rfc2460bis] as the maximum packet
>>     size.
>>
>> I searched for "IPv6 minimum link MTU" in draft-ietf-6man-rfc2460bis-09,
>> and could not find that term.
>> Even unlikely at this point in the IPv6 implementation cycle, we don't
>> want readers to believe that they should look at the minimum of the
>> device IPv6 MTU link(s).
>> Proposal: define "IPv6 minimum link MTU" as 1280 octets in 2460bis, or in
>> both documents.
>>
>>
>> ----------------------------------------------------------------------
>> COMMENT:
>> ----------------------------------------------------------------------
>>
>> In this document, I see:
>>
>>     IPv6 nodes SHOULD implement Path MTU Discovery in order to discover
>>     and take advantage of paths with PMTU greater than the IPv6 minimum
>>     link MTU [I-D.ietf-6man-rfc2460bis].  A minimal IPv6 implementation
>>     (e.g., in a boot ROM) may choose to omit implementation of Path MTU
>>     Discovery.
>>
>> In draft-ietf-6man-rfc2460bis-09:
>>     It is strongly recommended that IPv6 nodes implement Path MTU
>>     Discovery [RFC1981], in order to discover and take advantage of path
>>     MTUs greater than 1280 octets.  However, a minimal IPv6
>>     implementation (e.g., in a boot ROM) may simply restrict itself to
>>     sending packets no larger than 1280 octets, and omit implementation
>>     of Path MTU Discovery.
>>
>> So a SHOULD in one document versus "strongly recommended" in the other.
> Well.. isn't SHOULD == RECOMMENDED in RFC2119-speak?
Yes, but SHOULD <> "strongly recommended"
Just be consistent.

Regards, Benoit
>
> Cheers,