Re: [IPFIX] [Technical Errata Reported] RFC7012 (3852)

"Stewart Bryant (stbryant)" <[email protected]> Tue, 31 Dec 2013 09:36:54 +0000
Newsgroups gmane.ietf.ipfix
Message-ID <[email protected]>
Certainly something is needed. I was thinking of using IPFIX as an information gathering method in a radio context, and went to look at the definition of the types and could not find the epoch, or even a reference to the epoch. Now part of the problem (which was my fault) was that I did not notice at the time that the elements were defined by the obsolete RFC5102 and went straight to the new RFC. However having the definitions in an obsolete RFC also seems problematic, since it puts the IEs in a strange state. Since RFC 7012 replaces RFC5102 and includes the definitions you would expect the definition in RFC7012 to replace the definition in RFC5102, but those definitions are, as I explained incomplete. I need to look at this some more when I get back to work, but I am now also concerned that if the epoch can change, the definition of the existing IEs is now unreliable.

You will notice in the errata that I did suggest that an alternative resolution would be to include a reference to the epoch text.

Stewart



Sent from my iPad

> On 31 Dec 2013, at 08:50, "Brian Trammell" <[email protected]> wrote:
> 
> hi Paul, all,
> 
> +n.
> 
> The separation between ADTs and ADT encoding between 7012 and 7011 was explicit and purposeful. Specifically, we do _not_ want to exclude other representations of the IPFIX Information Model from being based upon other encodings of these ADTs, whether ISO 8601 (which either has no epoch or epoch 0000-00-00 00:00 UTC, depending on how you count), NTP (1904), Julian day based counting, etc, etc, etc…
> 
> If there is confusion on this point, I’d suggest adding more explanatory text on this point to Paragraph 2 of the front matter to section 3.1. But as is, I emphatically recommend rejection of this reported erratum.
> 
> Best regards,
> 
> Brian
> 
>> On 31 Dec 2013, at 03:58, Paul Aitken <[email protected]> wrote:
>> 
>> +1
>> 
>> If anyone was going to raise an errata on this, it would have been me ;-)
>> 
>> I've pointed this issue out before, probably more than once - and have been encouraged to read RFC 3444.
>> 
>> P.
>> 
>> 
>>> On 30/12/2013 09:23, Andrew Feren wrote:
>>> The encoding for the time data types is specified RFC 7011 Sections
>>> 6.1.7 through 6.1.10.
>>> 
>>> -Andrew
>>> 
>>>> On 12/30/2013 10:13 AM, RFC Errata System wrote:
>>>> The following errata report has been submitted for RFC7012,
>>>> "Information Model for IP Flow Information Export (IPFIX)".
>>>> 
>>>> --------------------------------------
>>>> You may review the report below and at:
>>>> http://www.rfc-editor.org/errata_search.php?rfc=7012&eid=3852
>>>> 
>>>> --------------------------------------
>>>> Type: Technical
>>>> Reported by: Stewart Bryant <[email protected]>
>>>> 
>>>> Section: 3.1.15-17
>>>> 
>>>> Original Text
>>>> -------------
>>>> 3.1.15. dateTimeSeconds
>>>> 
>>>>   The type "dateTimeSeconds" represents a time value expressed with
>>>>   second-level precision.
>>>> 
>>>> 3.1.16. dateTimeMilliseconds
>>>> 
>>>>   The type "dateTimeMilliseconds" represents a time value expressed
>>>>   with millisecond-level precision.
>>>> 
>>>> 3.1.17. dateTimeMicroseconds
>>>> 
>>>>   The type "dateTimeMicroseconds" represents a time value expressed
>>>>   with microsecond-level precision.
>>>> 
>>>> 3.1.18. dateTimeNanoseconds
>>>> 
>>>>   The type "dateTimeNanoseconds" represents a time value expressed with
>>>>   nanosecond-level precision.
>>>> 
>>>> 
>>>> Corrected Text
>>>> --------------
>>>> 3.1.15. dateTimeSeconds
>>>> 
>>>>   The type "dateTimeSeconds" represents a time value in units of
>>>>   seconds based on coordinated universal time (UTC).  The choice of an
>>>>   epoch, for example, 00:00 UTC, January 1, 1970, is left to
>>>>   corresponding encoding specifications for this type, for example, the
>>>>   IPFIX protocol specification.  Leap seconds are excluded.  Note that
>>>>   transformation of values might be required between different
>>>>   encodings if different epoch values are used.
>>>> 
>>>> 3.1.16. dateTimeMilliseconds
>>>> 
>>>>   The type "dateTimeMilliseconds" represents a time value in units of
>>>>   milliseconds based on coordinated universal time (UTC).  The choice
>>>>   of an epoch, for example, 00:00 UTC, January 1, 1970, is left to
>>>>   corresponding encoding specifications for this type, for example, the
>>>>   IPFIX protocol specification.  Leap seconds are excluded.  Note that
>>>>   transformation of values might be required between different
>>>>   encodings if different epoch values are used.
>>>> 
>>>> 3.1.17. dateTimeMicroseconds
>>>> 
>>>>   The type "dateTimeMicroseconds" represents a time value in units of
>>>>   microseconds based on coordinated universal time (UTC).  The choice
>>>>   of an epoch, for example, 00:00 UTC, January 1, 1970, is left to
>>>>   corresponding encoding specifications for this type, for example, the
>>>>   IPFIX protocol specification.  Leap seconds are excluded.  Note that
>>>>   transformation of values might be required between different
>>>>   encodings if different epoch values are used.
>>>> 
>>>> 3.1.18. dateTimeNanoseconds
>>>> 
>>>>   The type "dateTimeNanoseconds" represents a time value in units of
>>>>   nanoseconds based on coordinated universal time (UTC).  The choice of
>>>>   an epoch, for example, 00:00 UTC, January 1, 1970, is left to
>>>>   corresponding encoding specifications for this type, for example, the
>>>>   IPFIX protocol specification.  Leap seconds are excluded.  Note that
>>>>   transformation of values might be required between different
>>>>   encodings if different epoch values are used.
>>>> 
>>>> 
>>>> Notes
>>>> -----
>>>> Although section 1.1 says : - "Definitions of timestamp data types have been clarified." The edited text has removed the epoch definition, and this does not seem to have been incorporated elsewhere in the RFC.
>>>> 
>>>> Without a specified epoch, there is no unique definition of the timestamps.
>>>> 
>>>> My proposal above is to revert to the RFC5102 definitions. RFC7102 is intended to be backwards compatible with RFC5102 and thus the definitions need to be technically identical. Alternatively, if the text is now included elsewhere in RFC7012 or in another RFC, it would be helpful to the reader to provide a reference to the epoch definition in an editorial update to dateTimeX definitions in RFC7102.
>>>> 
>>>> Instructions:
>>>> -------------
>>>> This errata 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 (IESG)
>>>> can log in to change the status and edit the report, if necessary.
>>>> 
>>>> --------------------------------------
>>>> RFC7012 (draft-ietf-ipfix-information-model-rfc5102bis-10)
>>>> --------------------------------------
>>>> Title               : Information Model for IP Flow Information Export (IPFIX)
>>>> Publication Date    : September 2013
>>>> Author(s)           : B. Claise, Ed., B. Trammell, Ed.
>>>> Category            : PROPOSED STANDARD
>>>> Source              : IP Flow Information Export
>>>> Area                : Operations and Management
>>>> Stream              : IETF
>>>> Verifying Party     : IESG
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