COMMUNICATIONS STANDARDS REVIEW
Volume 12, Number 22 June 4, 2001
REPORT OF TR-30.3, DATA COMMUNICATIONS EQUIPMENT EVALUATION AND NETWORK INTERFACES, APRIL 30 – MAY 1, 2001, WILMINGTON, DE
The following report represents the view of the reporter and is not the official, authorized minutes of the meeting. TR-30.3, Data Communications Equipment Evaluation and Network Interfaces, April 30 - May 1, 2001, Wilmington, DE...... 2 Liaisons...... 2 PN-3509, Revision of TSB38 (Test Procedures for Evaluating Modem Performance)...... 2 PN-3857, North American Telephone Network Transmission Model for Evaluating Analog Client and Digitally Connected Server Modems...... 4 PN-4254, Network Access Transmission Model for Evaluating xDSL Modem Performance (TIA/EIA 876)...... 4 PN-4255, Test Procedures for Evaluating xDSL System Performance...... 4 TR-30.3 Attendance Roster, April 30 – May 1, 2001, Wilmington, DE...... 6 Acronym Definitions...... 7 Communications Standards Review Copyright Policy...... 8
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June 4, 2001 Vol. 12.22 Copyright © CSR 2001 1 COMMUNICATIONS STANDARDS REVIEW REPORT OF TR-30.3, DATA COMMUNICATIONS EQUIPMENT EVALUATION AND NETWORK INTERFACES, APRIL 30 - MAY 1, 2001, WILMINGTON, DE Note: The TR-30.1 and TR-30.2 reports were published in CSR 12.20, May 15, 2001. TR- 30.5 did not meet. J. Douglass (Conexant/Mindspeed) is the TR-30.3 chair. TR-30.3/01-04-028, Report of Meeting #111, St. Petersburg, Florida (March 2001), was accepted with minor changes. TR-30.3/01-04-029 is the Assignment List from the March 2001 TR-30.3 Meeting. TR-30.3/01- 04-029A is the updated Assignment List from this meeting. TR-30.3/01-04-035A is the April 2001 Document Register. TR-30.3/01-04-037 is the TR-30.3 draft Project Status from Communications Standards Summary (published by CSR).
Liaisons TR-30.3/01-04-044, Liaison from NRIC V, Focus Group 3 “Wireline Network Spectral Integrity” from E. Eckert (Chairman, NRIC V Focus Group 3), includes the Network Reliability and Interoperability fifth Council (NRIC V) Focus Group 3 status report and recommendations as presented to the Federal Advisory Committee. The purpose of this FCC-chartered committee is to provide recommendations to the FCC and to the telecommunications industry that, when implemented, will assure optimal reliability and interoperability of public telecommunications networks. The recommendations of NRIC V Focus Group 3 support the activities under way in Committee T1, TR-41, DSL Forum and the ITU SG15 Question 4. See
PN-3509, Revision of TSB38 (Test Procedures for Evaluating Modem Performance)
Work continued on PN-3509, Test Procedure for Evaluation of 2 Wire 4 kHz Voiceband Duplex Modems (to become TIA/EIA-3800). TR-30.3/01-04-025 is a summary of comments on PN-3509, prepared at the TR-30.3 meeting in St. Petersburg (March, 2001). TR-30.3/01-04-032, PN-3509 Draft 16, was prepared by editors E. Schulz (Agere) and G. Bretting (Compaq). TR-30.3/01-04-030 (G. Bretting, Compaq) is proposed text for PN-3509 section 5.2.4, Throughput over a sustained circuit. TR-30.3/01-04-031, V.92 Test Procedures (W. Henderson, Henderson Labs), provides procedures in eight areas for testing: • Throughput vs. Network Model Coverage (i-model) • Throughput vs. Network Model Coverage (u-model) • PCM Upstream • Call Connect Reliability (CCR) – {and fast connect feature performance} • Modem-on-Hold (MOH) – Functionality / Compatibility
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• Fast Connect • Block Acknowledgement and Character Echo Delay • Procedures specific to V.44, Data Compression TR-30.3/01-04-038, Comments on PN-3509 (A. Torres, Vocal Technologies), provides editorial comments regarding references and table numbers. TR-30.3/01-04-038A includes TR-30.3’s responses to these comments. TR-30.3/01-04-039, V.44 Test Files (W. Henderson, A. Clark, Henderson Labs), proposes modem test files, based on research conducted by A. Clark (Telchemy) with the objective of identifying a set of files that would objectively evaluate lossless compression algorithms. These files were presented as a contribution to ITU Study Group 16 Question 10 and TR-30.1 for use in comparison testing of specific data compression algorithms and to TR-30.3 for use in evaluating transmission products that implement compression schemes. Individual file construction is based on the concept that Internet traffic is a complex construction of diverse content files. TR-30.3 selected a set of application files, including CAD, Database, Facsimile, Graphics, Spreadsheet and Word Processing file types. Included, as well, are files that represent languages other than English. In addition to specifically “Internet-type” files, TR-30.3 submitted for consideration one file from previous evaluation standards. File “4.tst”, a highly non-compressible file, has been part of the testing repertoire for many years and, as noted later in this contribution, serves a unique purpose in product evaluation. The selection of the proposed files was based on evaluating the Entropy and Compression Ratio values for all considered files. TR-30.3/01-04-040, Modem on Hold Test Issues (G. Smock, Rochelle Communications), discusses some of the test issues that relate to the Modem-on-Hold feature of the V.92 standard. It covers the need to simulate and check proper detection of call waiting, CPE Alerting Signal (CAS), and Caller ID signaling by client modems. It asks some questions regarding the client modem’s ability to signal its detection of call waiting and CAS tones. Finally, It discusses two test configurations: A series pass-through configuration allows the use of a tester in conjunction with a telco line or another modem tester. A digital configuration will enable the testing of MOH function with a direct connection to a T1-equipped Remote Access Server (RAS). E. Schulz (Agere) agreed to provide V.92/V.44 client modem code to W. Henderson for PN-3509 V.92 / V.44 modem testing. W. Henderson will perform following tests associated with V.44: • Run proposed V.44 test files on modems with V.44 capability • Compare full V.44 test files to truncated 32 Kbyte V.44 test files • Compare V.42bis performance to V.44 performance • Run V.44 test files on two clients modems with two servers • Draft PN-3509 section on throughput vs. file type • Draft Rationale for test file types W. Henderson (Henderson Labs) will get Calgary Corpus test files from G. Pfeiffer (Telogy Networks). These files will be considered for V.44 testing. E. Schulz (Agere) will provide a new draft of PN-3509. Changes will be based on the following: • Instructions in editor’s notes • Issues list • TR-30.3/01-04-025, Summary of Comments on PN-3509 • Edits made to TR-30.3/01-04-032, Draft 16. • TR-30.3/01-04-038A, Response to VOCAL Technologies comments on PN 3509
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TR-30.3 discussed methods for adding Call Waiting and Caller ID functions using existing lab equipment. J. Douglass (Conexant/Mindspeed) will set up a conference call to discuss PN-3509 on June 14 at 11:00 PDT.
PN-3857, North American Telephone Network Transmission Model for Evaluating Analog Client and Digitally Connected Server Modems
TR-30.3/01-04-034, Proposed Draft Supplement to T1.403.02 to Add Informative Annex on V.90 Modem Compatibility (P. Dillon, Marconi Communications), provides an informative annex on V.90 modem compatibility (Annex A, V.90 modem compatibility with certain robbed-bit signaling patterns). This contribution is a revision of T1E1.3/2001-009, and contains the changes agreed by working group T1E1.3 at their February meeting.
PN-4254, Network Access Transmission Model for Evaluating xDSL Modem Performance (TIA/EIA 876) PN-4255, Test Procedures for Evaluating xDSL System Performance
TR-30.3 agreed to review ETSI Permanent TM6 (98)10, Laboratory Performance Tests for xDSL Systems (TR-30.3/01-03-021©, see CSR 12.14) to determine if it can be used as a basis for creating an international version of PN-4254.
TR-30.3/01-04-026, Test Loop Scores for xDSL Project (R. Perez, Telcordia), provides statistical results from the Telcordia Loop Survey. The Telcordia Loop Survey was a statistical sampling with a 95% confidence level (i.e., 5% error factor). A total of 1947 loops were randomly obtained and analyzed. The work done for TR-30.3 xDSL project was to extract the non-loaded pairs with a maximum length of 18,500 feet. A set of 13 test loops were developed with specific bins and the scores were presented as displayed in the column labeled “Telcordia 1997 Non-Loaded.” The Anonymous 2000 data shows only 87% of the total population. The fourth column shows the normalized scores that total 100% of the Anonymous 2000 data. The fifth column is the scores of all the loop population up to 18,500 feet from the Telcordia survey. The last column shows the scores of the total Telcordia survey. It is noted that these scores are much closer to the Anonymous 2000 data. This would suggest that the loaded cable pairs are in that population. If those pairs were removed, the data would be closer to the original Telcordia contribution. This can be supported by the scores in the column labeled “Total 1947 L & NL.” It is recognized that 92 test channels may be too time consuming for some modem evaluation processes. Therefore, TR-30.3 has specified four alternative truncated sets of test channels, representing decreasing coverage of the network models. All truncations are performed by eliminating a percentage of the cross product values found in Table 33. This gives the tester the flexibility to trade the accuracy of resultant estimate of network model coverage for reduced testing time. However, it is important to note that the models themselves are the result of significant compromise, and simplifications of the testing may result in masking differences that are key to individual potential users. TR-30.3/01-04-027A, Test Reduction Tables for PN-4254 (B. Giese, Motorola), provides five tables of data, from 80% to 100% coverage, with varying numbers of test channels. TR-30.3/01-04-033, Email from an anonymous source concerning more information about digital loop data for PN-4254 (J. Douglass, Conexant/Mindspeed), notes that the data presented in TR- 30.3/01-03-022 (see CSR 12.14) was a survey of all lines including DLCs, hosts, remotes; anything that had a testhead. The rule of thumb in the data is that anything over 18 K would have a load coil. More specifically, in a mixed gauge environment, one needs to satisfy the state PUC's requirement
4 Vol. 12.22 Copyright © CSR 2001 June 4, 2001 COMMUNICATIONS STANDARDS REVIEW for a grade of quality for the POTS service. This translates to a 1 kHz loss of less than 8 dB from the mainframe to the customer premises. If the cable is all 26 gauge, then the unloaded limit is around 13 kFt. If it is all 24 gauge, it is 17.5 kFt (hence the rule of thumb of 18 kFt). If it has 22 gauge and 19 gauge included, it could be up to 20 or 22 kFt for all 19 gauge (very rare). The source notes that this was just a length study. He also notes that for his lines that are less than 16 kFt, he finds about 5% to 7% of them are loaded for some reason. This is mostly because of "left in" load coils that are present because of cable throws during outside plant re-arrangement of cables, not by design. There is a percentage of them that are there by design because the loop is mostly 26 gauge. He does not know what that percentage is. TR-30.3/01-04-041 provides additional Digital Test Loop Data from an anonymous source (contributed by J. Douglass, Conexant/Mindspeed). It includes a sample of lines showing unloaded, DSL and DLC lines. The data is statistically random from across the US except the North East. It was taken in January through March of 2001. There are no loaded lines included in the data even though loaded lines as short as 300 feet were observed in the data. The curve of the unloaded lines matches the previously submitted bulk data pretty well. TR-30.3/01-04-036, DSL Forum Liaison regarding DSL testing and interoperability (G. Young, DSL Forum Chair), notes that the DSL Forum would appreciate receiving copies of draft EIA/TIA- 876. The ability to compare dynamic interoperability (performance) of many xDSL modems, for loops on a worldwide scope, is of interest to the DSL Forum, and they would like to discuss the details of TR-30.3’s approach further. DSL Forum is interested in applying the NMC methodology specified in draft EIA/TIA-876 in future DSL Forum technical reports and test plans. The DSL Forum Testing & Interoperability Working Group would like to hold a joint session with TR-30.3 regarding the DSL Forum WT-051 (ADSL Dynamic Interoperability Testing) and network models for xDSL testing, at their June meeting in Oslo. This liaison includes a copy of the most recent draft of WT-051. P. Kyees (Paradyne) plans on attending the next DSL Forum Meeting in Oslo, and will represent TR-30.3 at the joint meeting. Several TR-30.3 committee members may attend the DSL Forum meeting August 27-31 in New Orleans. TR-30.3/01-04-042 and TR-30.3/01-04-042A (C. Ventrillon, Spirent Communications) are Spirent’s comments on EIA/TIA-876 (PN-4254). Spirent voted yes and offered some ways to simplify the simulation and testing of the model. The comments were basically accepted as described in TR-30.3/01-04-042B which comprises TR-30.3’s responses to Spirent’s comments. TR-30.3/01-04-043 is the current draft of TIA/EIA-876 (PN-4254), and the presentation given to the DSL Forum (J. Douglass, Conexant/Mindspeed; P. Kyees, Paradyne). This draft of TIA/EIA- 876 needs to be validated before sending it out for industry ballot. It will be initially validated using the following: 1. Spirent will create the initial set of noise shapes for Table 29 (Network Model Coverage = 100%) of TIA/EIA-876 Draft (PN-4254) for CT1 D Loops 1 to 13, Loop 1 CT1A – CT1C and loop 1 CT2D. 2. Spirent will simulate and measure Crosstalk PSD. 3. Paradyne will measure real and simulated Crosstalk PSD for five lines conditions from above set. The real PSD mask and simulated PSD Mask should be within +/- 5%. 4. Paradyne will measure throughput on real and simulated line using actual ADSL equipment for line conditions from the above set. Paradyne will compare the actual throughput to simulated throughput. 5. Henderson Labs will test throughput on the above line conditions using actual ADSL equipment with the Spirent simulator.
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Data from the anonymous source (TR-30.3/3/01-04-041) should be included, but differences between Telcordia and anonymous data need to be resolved. .J. Douglass (Conexant/Mindspeed) will ask the anonymous source the following questions concerning the anonymous loop survey: • Were new survey loop lengths derived from cable records? • How accurate are the loop lengths? • What was the method used to measure loop length? • Why are loop lengths statistically more spread out than in data provided Telcordia survey? • What can be done to reconcile the differences between the Telcordia survey and the anonymous survey? • What recommendations do they have for modifying Table A1 (Test Loop Scores as of 2002)? P. Kyees (Paradyne) will add a section concerning distribution of crosstalk coupling (not linear), using TR-30.3/00-01-608 (same as T1E1.4/99-527) as a reference, as presented to the January 2000 TR-30.3 meeting in Boca Raton (see CSR 11.02). P. Kyees (Paradyne) will provide text for a section on moisture, temperature effects, noise and pair imbalance. J. Douglass (Conexant/Mindspeed) will send a liaison to T1E1.7 about loop battery characteristics. J. Douglass (Conexant/Mindspeed) will set up a conference call on June 13 11:00 PDT to discuss PN-4254. Jack Douglass, Conexant/Mindspeed
TR-30.3 Attendance Roster, April 30 – May 1, 2001, Wilmington, DE
Jack Douglass (Conexant/Mindspeed) TR-30.3 Chair 3Com Fred Lucas Agere Systems (formerly Lucent) Ed Schulz Cisco Andrew Stachur Conexant/Mindspeed Jack Douglass ESS Technology Jordan Cookman Henderson Communications Labs Warren Henderson Paradyne Philip Kyees Rochelle Communications Gary Smock Spirent Communications Carlos Ventrillon Telebyte Ken Schneider Telogy Networks Greg Pfeiffer Vocal Technologies, Ltd. Alberto Torres
6 Vol. 12.22 Copyright © CSR 2001 June 4, 2001 COMMUNICATIONS STANDARDS REVIEW ACRONYM DEFINITIONS ADSL Asymmetric Digital Subscriber Line CAD Computer Aided Design CPE Customer Premise Equipment DLC Digital Loop Carrier DSL Digital Subscriber Line EIA Electronic Industry Association ETSI European Telecommunications Standards Institute FCC Federal Communications Commission (U.S.) ID Identification IEEE Institute of Electrical and Electronic Engineers ITU International Telecommunication Union MOH Modem on Hold NMC Network Model Coverage PCM Pulse Code Modulation POTS Plain Old Telephone Service PSD Power Spectral Density PUC Public Utilities Commission SG Study Group (ITU) TIA Telecommunications Industry Association TM Transmission and Multiplexing (ETSI Committee) TR Technical Requirements (TIA committee) TSB Telecommunications Systems Bulletin (TIA) xDSL all the different Digital Subscriber Line technology
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