Subject: [Adslmib] Suggested Corrections to Performance Parameters: [Comments on Ver 06 draft VDSL-LINE-MIB]

From: "Umberto Bonollo" <[email-masked]>
Date: Wed, 6 Nov 2002 18:43:12 +1100

Hi Bob and Rajesh,

Some comments/suggestions on Ver 06 performance parameters:

1. The following are all in the 0..900 seconds range
within a 15 min interval:
vdslPerfCurr15MinLofs              HCPerfCurrentCount,
vdslPerfCurr15MinLoss              HCPerfCurrentCount,
vdslPerfCurr15MinLprs              HCPerfCurrentCount,
vdslPerfCurr15MinESs               HCPerfCurrentCount,
vdslPerfCurr15MinSESs              HCPerfCurrentCount,
vdslPerfCurr15MinUASs              HCPerfCurrentCount;

but

HCPerfCurrentCount is Counter64 (0..18446744073709551615).
Q1. Do we really need range 0..18446744073709551615 to hold
0..900 value?

2.
Also, vdslPerfCurr15MinInits is :
"Count of the line initialization attempts during this [15 min!]
interval.  This count includes both successful and
failed attempts."
Q2. Does it need such a large range for this ?
Ans2: Unsigned32 (0..65535) is probably OK.
(Remember also that Counter64's don't translate
to SMIv1, so use them sparingly.)

3. Unlike RFC 2662, the variable:
vdslPerfCurr15MinLols        HCPerfCurrentCount,
is missing in the VDSL-LINE-MIB (i.e. Loss of Link Seconds)
even though the alarm for it (Loss of Link) is defined in
in vdslCurrStatus (which is identical to adslAtucCurrStatus of RFC 2662).

Q3. Shouldn't we add: vdslPerfCurr15MinLols?

Regards,
Umberto Bonollo ([email-masked])
NEC Australia
&
Andrew Cheers
NEC Australia

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From: "Bob Ray" <[email-masked]>
Date: Wed, 27 Nov 2002 09:53:56 -0600

Umberto Bonollo wrote:

>Unlike RFC 2662, the variable:
>Shouldn't we add: vdslPerfCurr15MinLols?

In Atlanta, I promised to double check this bit.

As I read the standards documents, loss of link occurs whenever
there is loss of signal.  Obviously, when there is loss of link,
there is no functioning EOC.  This *may* explain why there is no LOL 
bit defined in the EOC ;)

Referring to the following generic diagrams

1.  ETSI TS 101 270-1 V1.2.1 (1999-10), section 10.1.1, Figure 16
2.  T1E1.4  T1E1.4/2000-000R3, section 11.1.1, Figure 11.1

I would expect the LOL bit to be set whenever the transceiver
is in the state "Warm-Start" (T1E1) or "Trying Warm Start" (ETSI).

There are no counters in the standards documents I read that directly
support "number of seconds in warm-start" (probably because they
are not in the EOC for the reason noted above).  The MIB thus 
presumes that the transceiver state is available to the agent in some
form.  The MIB does not presume that the number of seconds the 
transceiver is in the "Warm-Start" state is available (without
placing an undue burden on the agent).  I believe this same
presumption was made in the case of ADSL as well.

Does anyone think this should be added to the description(s)
of LOL in the text?

Also, the description of vdslThresh15MinLoss has a minor (cut-and-paste)
error in that it states "loss of frame" when it should state "loss of 
signal".

Similarly, the description of vdslThresh15MinLprs states "loss of frame" 
when it should state "loss of power".

HTH.  Also, I hope it is accurate. 

Bob Ray