Tx-Rx loss plan and Tone Table

Collegues,
 
The email chain on these topics has been quite active begining with IPCDN Digest, Vol 13, Issue 2 and through Issue 8.
 
I would like to make a few comments at this time.
 
The original submission to re-establish the Tx-Rx gain/loss requirement was submitted to the distribution list on 15 February, 2005.  So the reason and rational for this re-statement goes back 4 MONTHS not 5 days. In that submission a number of Telephony standards across world markets were identified and quoted and the rational for the return of the requirements was stated.
 
There are several points in the current gain/loss plan discussion.
1.  Should the Tx-Rx gain/loss requirements be in the SigMIB?
2.  If they are to be included, what is the range of values
3.  If they are to be included, what are the default settings.
 
The current view of the respondents tends to focus on the need for the requirements in the SigMIB.  This implies that no one has recognized the need to change the gain/loss requirement on any dynamic basis, either on a per call basis or within a call.  Without support for this in the SigMIB, the gain/loss requirement becomes fixed either by physical hardware design or vendor specific provisioning MIB approaches.
 
The questions on the range of values and defaults are a "mute point" if the basic Tx-Rx gain/loss is removed, however some considerations.
1.  PacketCable defines gain/loss at -2 dB
2.  ETSI defines gain/loss up to -11 dB
3.  Most operators and field experience tend to set the loss to -4 dB.
3.  Some worldwide operators tend to select values within these settings.
4.  Based on the various standards or operator requirements, a range of 0 to -12 dB of gain (0 dB to 12 dB loss) seems acceptable.
5.  Based on the various standards or operator requirements it would appear Tx gain and Rx gain in PacketCable architectures should default to 4 dB but ETSI based architectures should default to Tx at 4 dB but Rx at 11 dB.
6.  Operators may defined other defaults based on local requirements.
 
However, since the group appears to believe a "fixed" gain/loss plan is adequate, then Motorola withdraws the 15 February, 2005 proposal to re-instate the requirements and the discussion of range and default settings are a mute point.
 
This decision will also impact the pktcSigDevToneDbLevel since this requirement references the pktcNcsEndPntConfigRxGain entry.
 
The other point of discussion and the one which is more significant is the Tone table structure.  During the earlier SigMIB review process some problems were found with some international tone requirements with the original four frequency structure.  Proposal to that structure were submitted to the working group to resolve the problems seen at that time.  During review of this proposed change, one of the "MIB Doctors" required a change to the structure to "simplify" the structure.  Apparently the review of the MIB Doctor re-structuring of the Tone table focused on the problem at hand but failed to fully review previous tone structures.  This has resulted in the current situation where the current SigMIB draft fails to meet the requirements of the original PacketCable Supervisory Tones such as ROH Tone which is generated by combining four tones at frequencies of 1400 Hertz, 2060 Hertz, 24
 50 Hertz and 2600 Hertz at a cadence of 0.1 second on, 0.1 second off, repeating.
 
At this time only one proposal to correct the ToneTable structure has been made and NO comments have been offered to provide alternate structures or to accept the submission as it.
 
Personally I must still review the proposed ToneTable change but it does seem the WG should re-focus their efforts on the significant issue at hand.
 
Regards,
 
Phillip Freyman
Distinguished Member of the Technical Staff
Science Advisory Board Associate
Motorola, Inc.
Connected Home Solutions IPS
IP System Engineering
21440 West Lake Cook Road
Deer Park, IL 60010

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