Re: IETF IPCDN Signaling MIB - Draft 3 - Last Call for Comments

> Issue #7 - definition of pktcSigDevToneDbLevel
...
> In the current draft-03, this object is specified as follows: 
>  
> pktcSigDevToneDbLevel    OBJECT-TYPE 
>     SYNTAX       Integer32 (-60..4) 
>     UNITS        "dbm" 
>     MAX-ACCESS   read-write 
>     STATUS       current 
>     DESCRIPTION 
>         " This is the decibel level at which tones could be 
>           generated at the a and b terminals (TE connection point)." 
>     DEFVAL { -4 } 
>     ::={pktcSigDevToneEntry 2 } 
...
> The combination of defining this at the analog interface along with
> the large range (specifically the very high value of 4) places certain
> restrictions on the DSP architecture in order to meet the worst case
> requirements.
...

It is not that I disagree a priori with the proposed change, it just
raises a few questions:

(1) The analog reference point seems the logical reference point to use,
    since this table is about signals that will be generated on the
    analog line. When the reference point is changed to the digital
    reference point, will this not be confusing for someone who wants to
    fill out the values in the table? Maybe that person will have to do
    a quick calculation to calculate what digital dB level he must
    provide to obtain the analog dB level he wants, but if this is the
    case, can the MTA not do this calculation?

    Second, just as a tought, would the problem also be solved by
    leaving the description of the object as it is, but changing the
    range limits?

(2) Does this discussion also apply to the pktcSigPulseSignalDbLevel
    object? In other words, I think the interpretation chosen for the
    tone dB level should also be the one for the pulse signal dB level,
    and clarified in the defintion of the latter as well.

    Also, is it intentional that the SYNTAX of the
    pktcSigPulseSignalDbLevel object is TenthdBm, and that it is
    Integer32 for pktcSigDevToneDbLevel?


Thanks,

David

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David De Reu
tComLabs
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Tel: +32 9 269 22 91 - Fax: +32 9 329 31 74
www.tComLabs.com
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