New GR - Generic Criteria in Support of DSL Line Diagnostics and Control
Introduction
Existing ADSL line performance data is garnered in an inconsistent manner with different commands and formats for each supplier's product. The data acquired and reported often lacks the accuracy and detail needed to diagnose line performance. Moreover, currently reported line data is often out of date with no capability for real-time data collection.
New ADSL2 and ADSL2+ (ITU-T standards G.992.3 and G.992.5) modems and DSLAMs should be capable of reporting a common set of line diagnostic parameters with specified accuracy, including transfer function H(f), quiet line noise spectrum QLN(f), and SNR(f). Aggregate parameters are also reported: loop attenuation, signal attenuation, SNR margin, attainable net data rate, and aggregate transmit power (far-end). Loop data can be garnered in "Initialization mode" using standard ADSL training, or "Diagnostics mode" can be invoked on-demand and can run single-ended. Additionally ADSL2 and ADSL2+ modems should be able to control the following parameters: the power transmitted by each tone, the bit loading per tone, the total transmit power, the bit rates, and SNR margins. These control parameters may be included in this GR if there is sufficient interest.
Project Scope
G.992.3 and G.992.5 only specify the diagnostics and control parameters, and not the exact methods and commands for reporting and controlling these parameters. Moreover, these diagnostics and control parameters may not be included on some modems that are otherwise compliant to G.992.3 and G.992.5. DSL Forum specifications for ADSL+ diagnostic and control parameters compliance, in draft WT-105, are minimal and so far are separate from the ADSL2+ interoperability tests in WT-100. Therefore, ADSL2+ modems may pass the interoperability tests defined by the DSL Forum without having standardized diagnostics and control parameters.
The issues to be addressed in the new GR will be decided by the industry participants, but are anticipated to include:
- Functional requirements for DSL line diagnostics and control. This is to specify methods of testing compliance with the line diagnostics and control parameters defined in ITU-T ADSL and ADSL2+ standards G.992.3 and G.992.5. Also, test methods and pass fail criteria for the accuracy of reported DSL line diagnostics are to be specified. These may be generalized for use on any type of newer DSL modem (i.e., VDSL or VDSL2).
- Common specification of the TL1 command set required to obtain DSL line diagnostics in ITU-T ADSL and ADSL2+ standards G.992.3 and G.992.5. So far, there is no such common specification in the industry, and different command sets are now used to pull data from different vendors' equipment. It would be a tremendous benefit for operators to have such a common command set, allowing open, standards-based, operations systems. Common specification of the TL1 command set required to transfer G.992.3 and G.992.5 control parameters may also be included if there is sufficient interest. The TL1 command functionality in this new GR will be developed to be consistent with emerging new TL1 command specifications in GR-199-CORE and GR-833-CORE, which will run concurrently and have a slightly earlier estimated completion date.
Pursuant to the Telecommunication Act of 1996, relating to the development of industry-wide generic requirements, Telcordia invites all interested members of the industry to participate in the potential development of this proposed new GR. If your company is interested in participating in this activity, please contact Telcordia.
For More Information
Ken Kerpez
Telcordia Technologies, Inc,
One Telcordia Drive, Piscataway,
Room RRC 1N327,
Piscataway, NJ 08854-4182
Phone: (732) 699-2234
Tentative Schedule
Contact by: July 29, 2005
Project Start Date: August 2005
Estimated Completion Date: February 2006
Participation Fee: $23,000 for early sign-up, $26,000 otherwise