Subject: [ipfix-protocol] new version of the IPFIX protocol draft:draft-ietf-ipfix-protocol-17.txt

From: Benoit Claise <[email-masked]>
Date: Fri, 15 Jul 2005 00:27:13 +0200

Dear all,

A new version of the draft has been posted.
Two minor editorial changes:
    http://ipfix.doit.wisc.edu/archive/2875.html
    http://ipfix.doit.wisc.edu/archive/2876.html

Regards, Benoit.

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From: [email-masked] (Jon Kåre Hellan)
Date: Fri, 15 Jul 2005 14:49:24 +0200

Hi

Here's how the draft protocol specification defines
dateTimeNanoSeconds:

> 6.1.8   dateTimeNanoSeconds 
>    
>   The data type of dateTimeNanoSeconds represents a time value having 
>   a precision of nanoseconds and normalized to the GMT timezone.  It 
>   is encoded in a 64-bit integer according to the NTP format given in 
>   [RFC1305].  The high-order 32-bits represent the number of seconds 
>   1900 and the low-order 32-bits represent the fractional seconds with 
>   the fraction ranging from 0 - 2^(32-1) / 2^32.  This gives a maximum 
>   precision of about 200 picoseconds. 

Two problems here:

1. Both the first and the last sentence appear to define the precision,
   inconsistently. Changing the the first sentence to read "a precision in
   the order of nanoseconds" would fix this.

2. The range of the fraction given is approximately 0 - 0.5
   seconds. The intention is probably (0 - (2^32) - 1) / 2^32.

Regards

Jon Kåre Hellan, UNINETT

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From: [email-masked] (Jon Kåre Hellan)
Date: Fri, 15 Jul 2005 14:57:13 +0200

[email-masked] (Jon Kåre Hellan) writes:

Following up on myself, sorry!

>    the order of nanoseconds" would fix this.

The information model says:

3.1.13  dateTimeNanoSeconds

   The type "dateTimeNanoSeconds" represents a time value having a
   precision of nanoseconds and normalized to the GMT time zone.

and 5.8.7 flowStartNanoSeconds and 5.8.8 flowEndNanoSeconds both say
that the unit is nanoseconds.

Obviously, protocol and information model have to agree.

Regards

Jon Kåre Hellan, UNINETT

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From: Juergen Quittek <[email-masked]>
Date: Tue, 26 Jul 2005 11:32:28 +0200

Jon,

Thanks for this hint.  I think we need some clarification
here.  It looks like the terms 'unit' and 'precision' are
not used consistently in protocol and info model draft.

    Juergen