Re: Adam Roach's Discuss on draft-ietf-6man-maxra-03: (with DISCUSS and COMMENT)

[Bob Hinden <[e-mail]>]

Adam,

With my Doc Shepard hat on.

> On Oct 25, 2017, at 12:03 AM, Adam Roach <[e-mail]> wrote:
> 
> Adam Roach has entered the following ballot position for
> draft-ietf-6man-maxra-03: Discuss
> 
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> 
> 
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> I'm concerned that this normative statement is ambiguous (2nd paragraph of
> section 4), and that the ambiguity around allowed values may lead to interop
> issues:
> 
>   AdvDefaultLifetime
>   MUST either be zero (the router is not to be used as a default
>   router) or be a value between MaxRtrAdvInterval and 65535.
> 
>> From the text in section 3, I infer that MaxRtrAdvInterval is *not* an allowed
> value.
> 
>> From the "no greater than 65535" language, I infer that 65535 *is* an allowed
> value.
> 
> Please ensure that your normative statement here is very clear about whether
> "between" is intended to include its high and low limits as acceptable values.
> 

This doc is updating the text in RFC4681 which uses the same language:

 AdvDefaultLifetime

        MUST be either zero or between
        MaxRtrAdvInterval and 9000 seconds.

I read this as saying it should be more than MaxRtrAdvInterval and less than 9000.  Hence it is “between” the two values.

I am not aware of interoperability problems caused by the RC4681 “between” language.  Can you point to a problem?  This doc is changing the maximum allowed values to 65535 seconds to avoid the effects of sending too few RAs on particular types of links.

I think the text is clear.  Please describe why you think it could cause an interoperability problem.

Thanks,
Bob


> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Section 4 contains:
> 
>   As explained in Section 3, the relationship between MaxRtrAdvInterval
>   and AdvDefaultLifetime must be chosen to take into account the
>   probability of packet loss.
> 
> The use of a non-normative "must" here indicates that you probably want to
> update your RFC2119 boilerplate to be RFC8174 boilerplate.
> 
>