RE: I-D ACTION:draft-ietf-ips-scsi-mib-04.txt

[Bill Studenmund <wrstuden@wasabisystems.com>]

On Wed, 30 Oct 2002, Amir Shalit wrote:

> I have two comments:
>
> 1) Read/Write counters
>
> Counter32 (counting MB transferred) wrap at about 1000 hours on 10Gbps
> links.
> Can we the MIB use a Counter64 instead?

Why?

Looking at the description of Countter64 in _Understanding_SNMP_MIBs_ by
Perkins & McGinnis, page 47, middle of "behavior" paragraph, "This type
may only be used when a 32-bit counter rollover could occur in less than
an hour. Otherwise the Counter32 type must be used."

While that book isn't an RFC, the authors know a lot about SNMP. I doubt
they would write the above if it weren't standard policy.

Looking at my copy of SNMPv2-SMI.txt, I also find:

-- for counters that wrap in less than one hour with only 32 bits
Counter64 ::=
    [APPLICATION 6]
        IMPLICIT INTEGER (0..18446744073709551615)

Digging around some more, in section 7.1.11of RFC 1442 (SMI for SNMPv2):

          A requirement on "standard" MIB modules is that the Counter64
          type may be used only if the information being modeled would
          wrap in less than one hour if the Counter32 type was used
          instead.

So since 1000 hours >> 1 hour, looks like RFC 1442 says, no we can't use a
counter64.

Take care,

Bill