Re: PerfHist-TC-MIB

[Rajesh Abbi <[e-mail]>]

Jeff,

You are correct about the UAS definition as per ANSI T1.231.  It is
somewhat 
absurd that a second that was 'available' in tha past may become
'unavailable' 
in the future, and vice-versa.

Any ANSI folks around to comment ?

Rajesh 

[e-mail] wrote:
> 
> > > I remember somewhere in the draft it is indicated that some values might
> > > decrease, i.e., not 'monotonically increasing'. For example, some seconds
> > > may be counted as "Errored Seconds" but later it is found that they should
> > > not be counted in (this decision can not be made any earlier), so you will
> > > have to subtract number of them (seconds) from the total count.
> > >
> >
> > Are you serious ?
> >
> > This is 'flaky behavior' in any equipment ! After a second has expired,
> > it was
> > either 'errored' or 'non-errored'.  If the equipment cannot make a
> > determination,
> > it cannot just increment the counter and change its mind later.
> >
> > I sure hope there is no such product out there.  Do you have one like
> > that ? ;)
> 
> anybody who has sonet equipment compliant with ANSI T1.231 has
> equipment like that.  an errored second is an errored second unless
> it's an unavailable second.  unfortunately you don't know if it's an
> unavailable second until up to 10 seconds in the future.  so if you're
> doing real-time couting in sonet equipment, you may have to "correct"
> counts up to ten seconds in the past as the interface moves in and out
> of unavailable time.
> 
> the latest sonet mib draft (draft-ietf-atommib-sonetng-02.txt) covers
> this in detail, as well as covers a mechanism that utilizes a
> 10-second shift register to avoid having to make the corrections.
> 
> /jeff