TELECOM ACCESS STANDARDS NEWSLETTER NO. 126 December 2000 CONTENTS 1. ADSL CPE TESTING 2. ADSL LINE FILTER TRIAL 3. LINE FILTER AND SPLITTER SPECIFICATIONS 4. REVISION OF PTC 270 5. ADSL CPE APPLICATION AND OPERATING SYSTEM SUPPORT 6. SUPPLY OF DIAGNOSTIC INFORMATION TO THE JETSTREAM HELP DESK 7. CHRISTMAS GREETINGS RETURN TO MAIN INDEX 1. ADSL CPE TESTING Telecom's ADSL CPE testing service has now closed, along with the Wellington ISDN testing, as mentioned in the last newsletter. ADSL testing is being transferred to independent laboratories in accordance with our preferred practices. I am pleased to announce that two of our accredited Telepermit testing laboratories have now had their accreditations "provisionally extended" to cover ADSL CPE. We have had Telecom and the other two laboratories conducting comparative testing of ADSL products over the past few weeks in accordance with our draft specification PTC 270. Now that are able to correlate Telecom's test results with those of TeleLab and Harvest Laboratories, we are accrediting them to take over this class of work. The ITU Recommendation has recently been published and we will align PTC 270 with the final version and with other matters that have arisen in service, such as those outlined below. This work may require consequential changes in our testing procedures, hence the provisional nature of these accreditations. Our main aim has been to make sure that ADSL CPE suppliers do not lose the opportunity to get their products tested, simply as a result of the closure of our own laboratory. Also, we prefer to have at least two testing laboratories able to carry out our testing work once it becomes a commercial enterprise. We recommended earlier that suppliers should carry out on-line practical testing in their own premises before submitting products for formal Telepermit testing, and we still stress that this is the best way of finding out what problems a typical customer would face in setting up a computer to operate on "JetStream". Because the quality of information given to customers is so important, we will now require the labs to verify basic functionality and confirm that the customer set-up information is correct (see item 4 below). Both laboratories carry out their testing "on-line" to "JetStream" (our own lab used a "captive" DSLAM) and will confirm that information can be downloaded from the Internet. Applicants for testing are to provide their "localised instructions" to the test lab, along with the sample for test. Failure to do this will only delay testing and our processing of any subsequent application. The address details and contact numbers of both laboratories are published on our website under "List of Accredited Laboratories", so will not be repeated here. 2. ADSL LINE FILTER TRIAL Notwithstanding our caution over the potential for radio interference expressed in Newsletter No. 123 and specification PTC 270, we are now conducting a limited trial of line filters (connected at individual jackpoints connecting POTS CPE). We have used splitters (a single unit connected at the network entry point) to date, mainly as a result of investigations carried out in the UK, which also uses 3-wiring in customers' premises. The UK Radiocommunications Agency has placed some fairly tight constraints on carriers offering ADSL services in order to minimise RFI. Fitting splitters at the entry point and considering them as "network equipment" meant that we could ensure the splitter met our specifications, install a separate balanced cable to the ADSL jackpoint, and reliably avoid RFI problems. This "safe approach" has the drawback that Telecom has to pay for the site visit by a contractor and these costs have to be passed on to the customers in the long term, despite our current free installation offers to promote "JetStream". A site visit is avoided overseas by having the customer purchase line filters to connect into each jackpoint connecting POTS CPE. These line filters provide isolation between the POTS CPE and the ADSL signals to prevent either interfering with the other. Unfortunately, the ADSL signals are still connected to the POTS wiring, hence our concerns about RFI. A very brief trial was carried out in Wellington to assess whether RFI would actually be noticeable with typical premises wiring, including our inherently unbalanced 3-wiring. The results were quite promising and we are now extending the trial to another 100 sites to determine whether RFI is going to be as significant a problem as we were led to believe. Telecom contractors are installing line filters as part of the trial so they can check whether they are effective. Our expectations are that line filters will be an acceptable solution for at least some customers. Assuming we can determine the range of conditions under which their use can give high assurance of satisfactory operation, we will be extending the use of line filters so that "JetStream" customers in general will be able to install them, along with third party-supplied CPE, subject to some overall guidelines. 3. LINE FILTER AND SPLITTER SPECIFICATIONS One of the problems with using line filters is that not only does each have some impact on the performance of the associated POTS CPE, but that anything from one to five of them may be connected on the same line. All filters remain connected to the line, whether or not the associated CPE is off-hook, and this can affect the return loss of the line. Adding to these complications, filters will vary in their characteristics and different types could well be connected on the same line. Assessing the overall impairment of such combinations and determining the technical parameters for filters can get quite complicated. Line filters installed within the customers' premises, will be regarded as CPE and be open to competitive supply. To support an open market for these components, we are working on a new PTC specification, which is hoped to be ready in the New Year. This work will be largely dependent on the success of the trial outlined above. 4. REVISION OF PTC 270 The interim specification for ADSL CPE, PTC 270, will be revised in due course, but our immediate need is to introduce some new requirements and enforce more rigidly the provision of suitable information to customers. a. At present, Telecom's JetStream uses PPPoA, as explained in PTC 270. The current test requirements include synchronising with the DSLAM and downloading information, which confirms that PPPoA has been implemented to at least a reasonable extent. However, in no way do these limited practical tests verify full compliance with RFC 2364. Telecom will be developing its ADSL services in a number of ways, but the overall approach will be that all such developments of the existing service will be in compliance with the PPPoA (RFC 2364) protocol. This has significance for CPE suppliers. Should a product "only more or less comply" with RFC 2364, there is a risk that network developments could lead to the product no longer being compliant with the network. To minimise this risk, we will now require that all applicants for ADSL CPE Telepermits arrange for the manufacturer to certify that the product fully complies with RFC 2364. This certification should preferably be from an independent testing authority, but where this is not available, it can be provided as a signed statement by the product manufacturer. b. Other likely developments include services using PPPoE. While these are not currently offered by Telecom, it is recommended that products offered for sale now should be capable of supporting this additional protocol, so that they will be suitable for use with such new services. I should stress that this requirement is optional, not mandatory. However, where PPPoE capability is claimed, it too should be supported by manufacturer or independent laboratory certification. ADSL CPE suppliers proposing to apply for Telepermits and those who already have Telepermits should note the above requirements "a" and "b", and provide the necessary certification(s) at the earliest opportunity. To give the usual 3 months notice of changes, these requirements will come into force on 1 March 2001. In the meantime, suppliers are urged to comply as soon as possible to minimise the risk that their products may be disrupted by network upgrades. c. As mentioned in Newsletter No. 125, we accepted that many Telepermit applicants had submitted their "generic" overseas user manuals pending some assurance that their products would meet local technical requirements. With over 20 products already Telepermitted, the technical requirements are obviously achievable by a wide range of suppliers and it is only reasonable that proper locally applicable instructions be provided. These should now be relatively easy to prepare given the generic instructions in Newsletter No. 125, and other information on our website. The URL for this is http://www.telepermit.co.nz/ADSLModemSetUp.html These generic instructions are to be "customised" to suit the particular wording used in the CPE set-up instructions. With JetStream lines now widely available, suppliers can also check the accuracy of their instructions before sending a new product to a test laboratory. As explained in item 1 above, we will now require the test lab to set up the CPE under test exactly in accordance with the customer set-up information provided by the supplier of the product. The lab will carry our basic on-line functional tests by downloading information from the internet. If the instructions are accurate, this will reduce the testing costs and enable the testing laboratory to verify that the set-up information is accurate and complete. If not, setting up will be more complicated and the lab will have to make corrections as part of their test report, all adding to the testing costs. With the wide range of different products being connected and the increasing rate of installation of "JetStream" services, it is imperative that CPE suppliers give customers accurate and complete set-up information as part of their product support responsibilities. We will now insist on seeing a copy of the proposed information sheet or revised User Manual before granting the Telepermit. This is a requirement of PTC 270 in any case. d. A related issue is the information given to customers regarding the sources of the initial set-up information necessary to commission the CPE and where to go for assistance in the event of trouble. Telecom has provided considerable assistance via its JetStream Help Desk, but much of its work to date has strictly been the responsibility of either the CPE supplier or the customer's ISP. It is important that User Instructions guide the customer to the most appropriate source of set-up information. It must also be made clear that Telecom is only to be approached where there is some clear indication that the network service is at fault. Telecom may have to charge for services where the customer equipment or set-up is the cause of a service problem. 5. ADSL CPE APPLICATION AND OPERATING SYSTEM SUPPORT Repeating advice in Newsletter No. 125, it is important that suppliers give clear information on what operating systems the CPE will run with and what applications are supported. e.g., whether or not the software supports an operating system (eg, Win 95, Win 98, Win ME, Win 2000, NT 4.0, Linux, and the various Mac OS). As explained in Newsletter No. 125, our aims are to avoid customers buying a product that does not meet their needs, and to avoid our Help Desk being called on to handle enquiries or complaints that something does not work when it was never intended to work. 6. SUPPLY OF DIAGNOSTIC INFORMATION TO THE JETSTREAM HELP DESK Another reminder - that we would like our Help Desk to be provided with a sample of each type of ADSL CPE, together with set-up software and user manual, so the staff can familiarise themselves with the product and assist customers with problems. Our aim is to be able to reliably determine whether a problem is network or customer equipment-related. It has been suggested that suppliers should also ensure that ISP's are given a reasonable level of support, as they are often going to be the first point of contact should the customer strike problems. It would be worthwhile to at least give the ISP's the brief summary of the diagnostic indications and their significance for each product, as suggested in Newsletter No. 125. Unfortunately, where ISP's and our Help Desk do not have the necessary information to help the customer, they will simply have to refer enquiries back to the CPE supplier. This could happen even when the fault is not directly CPE-related. 7. CHRISTMAS GREETINGS Richard Brent, Alan Reedy, Anna van der Lugt and I wish all our clients and readers a very Happy Christmas and New Year. In case some "Northerners" haven't realised, we "Southern Hemisphere" people take our summer break at this time, so the office will be closed after Friday 22 December and we will not be back until 8 January. DOUG BURRUS Manager Access Standards