Re: FW: 64 bit counters in MPLS MIBs

[Andy Bierman <abierman@cisco.com>]

At 06:07 PM 1/6/2003 +0100, Wijnen, Bert (Bert) wrote:
>I had suggested to MPLS MIB people that at places
>where they use parallel 64 and 32 bit counter (the
>32-bit values fo those systems that do not support 
>64bit), that it might be better to use just 64 bit
>and forget the 32 bit counters.
>
>This is what I am getting back. Any opinions/input
>or comments?

As Mike pointed out, the real issue is the expected rollover time
for the counter, not just the SNMPv1 vs. SNMPv2C issue that
Dave mentioned.

Remember the '1 hour rule'?  Remember the many discussions 
that led to the text in RFC 1573, sec. 3.2.6?  Remember that
we don't have Unsigned64 or Integer64 because some people
objected on the grounds a reasonable '1 hour rule' could
not be written for these types?

Well, we still have the '1 hour rule' in effect, and therefore
it would be inappropriate to tell the MPLS MIB people they
should remove their 32 bit counters.  The correct design
depends on the possible instances of the counter. For many
counters, this is to have both 32-bit and 64-bit counters 
and use conformance statements to specify which versions need 
to be implemented.  The 64-bit versions are named with an HC
in the descriptor (by convention).

This does not mean I supported the '1 hour rule', then or now.
The rule for Unsigned64 is so bloody obvious it's not
surprising we missed it: "I need to model a quantity that is 
greater than 2^^32." End of rule.


>I understand that we will NOT change the description
>of counter64 of course.
>
>Thanks,
>Bert 

Andy



>-----Original Message-----
>From: Thomas D. Nadeau [mailto:tnadeau@cisco.com]
>Sent: maandag 6 januari 2003 16:11
>To: Wijnen, Bert (Bert)
>Cc: Joan Cucchiara x302; Cheenu Srinivasan
>Subject: 64 bit counters in MPLS MIBs
>
>
>
>        I have a question RE: 64 bit counter changes
>in the MIBs.  During the MIB review, you (Bert) had
>suggested that we delete the counters called
>HC and change the type of the existing counters
>from 32 bits to 64 bits.   My question is when we
>support these on platforms that indeed do not
>support 64 bit counters, can we add something
>to the description that allows for this? I have been
>discussing this change with some developers
>here and have been getting serious push back
>based on the fact that on platforms that do not
>natively support 64 bit counters one must emulate
>them at the process level. On the surface this seems
>reasonable. However, when you look at the number of
>emulated counters in just say the LSR MIB which has
>per label counters (there can be 100,000s of labels),
>this starts looking very unpalatable very quickly.
>
>        So I think we either need to continue
>supporting the 32 bit versions and/or change
>the description of Counter64 to allow for a variation.
>
>        --Tom