Subject: [ipfix-info] draft-ietf-ipfix-info-01 issue: 64-bit timestamp type(s)

From: Simon Leinen <[email-masked]>
Date: Wed, 27 Aug 2003 21:52:00 +0200

The current -ipfix-info- draft specifies three types to represent
"specific instant[s] of time", namely dateTime, ipdr:dateTimeMsec, and
ipdr:dateTimeUsec, with second, millisecond, and microsecond
resolution, respectively.  DateTime can be represented in 32 bits, the
other two in 64 bits each.

I don't think all three of these types are useful.  In particular, if
you have ipdr:dateTimeUsec, why would you use ipdr:dateTimeMsec at
all?

My suggestion would be to define "dateTimeNsec", which would fit in 64
bits just as nicely as ipdr:dateTimeMsec and ipdr:dateTimeUsec, and
remove the latter two.

Suggested text changes:

4.15 (ipdr:dateTimeMsec) and
4.19 (ipdr:dateTimeUsec) should be removed and replaced with

    4.15 dateTimeNsec
    
    The "dateTimeNsec" type represents a specific instant of time.  It
    is further restricted from the basic XL dateTime type to having a
    precision of nanoseconds and normalized to the GMT timezone.
    
    Such types are in common use on many Operating Systems
    (e.g. "struct timespec" in POSIX.1b) and have the advantage that
    they can be stored in 64 bits.

Note that the text - for whatever timestamp types we decide to specify
- should say how the timestamps should be represented, i.e. relative
to what "epoch", and whether the integer components of the
representation should be interpreted as signed or unsigned.
-- 
Simon.

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