Understanding Your Broadband Quality of Service

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1 Understanding Your Broadband Quality of Service November 2004 PO Box Law Courts MELBOURNE VIC 8010 Telephone (03) Facsimile (03) TTY (03) ABN

2 Background The ACA has received feedback indicating consumer concerns with the comparability of, and confidence in, delivered broadband services. Broadband is taken to refer to alwayson services with a data rate greater than 200 kbit/s, including technologies such as Digital Subscriber Line (DSL), cable, satellite and wireless technologies. Descriptions of these technologies and services can be found on the ACA s Web site Internet Information Summary at and also in the Consumer Fact Sheet, A guide to Internet technology, at What does Quality of Service mean? For the purpose of this document, broadband Quality of Service only refers to measures of broadband technical performance. We exclude such support services as fault repairs, technical support, user applications, billing and help desks, as these issues are not unique to broadband. Primarily, Quality of Service measures can than be addressed by: (1) data rate, as measured by the speed achieved in transferring data from one point on a network to another; and (2) reliability, as measured by the probability that the service is available for use at any time. Is there a problem with broadband Quality of Service? The ACA conducted consumer consultative forums in June 2003 to seek feedback on the subject of broadband performance measures. The consumer forums identified users key concerns, and included the following items relevant to Quality of Service measures: Summary of issues Inability to compare one service offering with another. Difficulties with technical language and jargon. Concerns about actual performance of a service compared to advertised characteristics especially in relation to actual speeds and bandwidth availability. Lack of information about limitations or restrictions on services and what those limitations or restrictions mean in meaningful terms. How can broadband Quality of Service be measured? Because of the nature of the Internet, ISPs can only provide a best endeavours service, with a target data rate, but no guarantee that this will always be achieved. There are a many factors that can affect the customer s experience of an Internet connection that do not relate to the ISP. These include: the customer s PC, modem, and software; the application or content used by the customer, e.g. , music or video; the protocols used by Internet applications; capacity on shared domestic and international Internet resources; and the popularity and capacity of content providers Web resources. If ISPs were asked to provide details of their broadband network performance, their figures would typically consider only the performance of the link to the user, as all other - 1 -

3 aspects of the Internet experience are beyond the control of the ISP. This approach is accurate, but is less meaningful to consumers. The ACA therefore sought to investigate measures of broadband Quality of Service from the consumers perspective. The ACA s study of consumer measures of broadband Quality of Service. The ACA commissioned a study by Telco One Pty Ltd which involved the analysis of test results collected by the TCP/IQ Line Speed Meter over the period 1 July June The Line Speed Meter is downloaded voluntarily by users from an Internet site ( and runs from the user s PC. Typically, the users of the meter would be biased towards IT proficient consumers aiming to fine-tune their broadband service, or to test the advertised claims of their ISP. To measure data rates, the Line Speed Meter records the time taken to download a set of files, selected randomly from a list of popular web sites. Upload tests are conducted similarly using standard files. Test results therefore include issues outside the ISPs control, such as other applications accessing the user s broadband connection simultaneously, or high traffic to a Web site. These factors may influence the resulting data rate but reflect the consumer s real Internet experience. To estimate network availability, Telco One first determined the annualised average daily usage pattern for the Line Speed Meter in 10 minute blocks, as shown in Figure 1 below, which provides a good model of general broadband Internet usage. In simple terms, if the number of recorded tests in any 10 minute block was abnormally lower (three standard deviations below) the average usage for that particular 10 minute block, then the network was deemed to be unavailable Number of tests :00 12:00 14:00 16:00 18:00 20:00 22:00 0:00 2:00 4:00 6:00 8:00 Time of day (Eastern Standard Time) Figure 1. Model of daily Internet usage based on number of Line Speed Meter tests per 10 minutes - 2 -

4 Performance results ISP Network Availability. For network availability, the Line Speed Meter test results show that, for the subnetworks selected by state, ISP and technology, all are estimated as delivering above per cent availability, or less than two hours network downtime per month. Figure 2 below shows the availability for those sub-networks that had sufficient data on which to base estimates. The ACA has averaged the results over ISPs, by technology and state, to avoid comparative sensitivities. 1.5 AVERAGED OUTAGE HOURS PER MONTH TAS DSL WA Cable SA DSL ACT DSL VIC DSL WA DSL SA Cable NSW DSL NETWORK AVAILABILITY % % % % % % % % % % % % % % % % OUTAGE HOURS QLD Two way Sat QLD DSL NT DSL VIC Cable QLD Cable NSW Cable QLD One way Sat Figure 2. Estimated sub-network outage and availability What availability performance can I expect from my broadband service? The Telco One performance results show that, of the ISPs with sufficient test results to estimate network outages, the estimated network availability is better than per cent across all states, ISPs and technologies. This means that, as a user of a broadband service, you may expect that on average the network should be unavailable for less to two hours in any month

5 Performance results ISP Data Rate. The Line Speed Meter records the consumer s download and upload experience using the Internet, including a number of factors that cannot be controlled by the ISP. The key data rate observations from the Line Speed Meter analysis are: Average download rates tend to be very uniform for each technology, regardless of ISP or location, but achieve only around per cent of the advertised Plan data rate. While this observation is consistent with the impact of overheads due to Internet protocols and other external effects, it is considered unlikely that most consumers would be aware of this practical limitation to their contracted Plan. DSL results for download show little variability, with standard deviations only in the order of 10 per cent of the calculated mean data rate. Results for cable showed a significant level of variation, with standard deviation in the order of 40 per cent of the average data rate. This is consistent with the nature of cable being a shared resource from the user to the exchange, so that if there is only one user on-line the data rate will be very high, but each subsequent user shares the same bandwidth. Therefore, it is to be expected that the variability of cable data rate would be higher than for other broadband access solutions. Satellite results showed relatively low data rates achieved and high standard deviations. Some of the users of 512 kbit/s Plans achieved lower average download data rates than those with 400 kbit/s Plans. This outcome may reflect relatively fewer users and tests conducted. Compared with download, upload results are generally consistent for DSL, but satellite achieved lower data rates compared with Plan. Cable upload performance shows a very high level of variability. The key data rate results reported by Telco One are summarised in Table 1 below. Technology Plan (kbit/s) Average of ISPs Download (kbit/s) % Plan data rates Std Dev Average of ISPs Upload (kbit/s) % Plan data rates DSL 1500/ % 12% % 15% DSL 512/ % 11% % 24% DSL 256/ % 8% 53 83% 11% Cable UL/UL 3047 NA 41% 309 NA 283% 1-way Satellite 400/ % 31% 26 46% 4% 1-way Satellite 512/ % 32% 27 48% 19% 2-way Satellite 400/ % 31% No tests 2-way Satellite 512/ % 35% No tests Table 1. Average of Measured Data Rates by Technology Std Dev - 4 -

6 What data rate performance can I expect from my broadband service? There is an apparent discrepancy between advertised data rates and the actual download and upload rates experienced by consumers, depending on the access solution used by a consumer. The data protocols used to communicate over the Internet may need up to 20 per cent of the capacity of the broadband link. Further, because of the best endeavours nature of the Internet, the factors outside an ISP s control, and the daily variation in Internet traffic, the data rate that a consumer experiences may vary. As a broadband user, you need to be aware that the data rate of the ISP s access Plan is the maximum data rate. The effective data throughput that you will achieve will vary from time to time, and in general may average up to 20 per cent lower than the Plan rate. This is normal broadband operation. Performance results in regional areas. The Telco One study examined the Line Speed Meter data rate results across multiple geographic criteria state, ABS remoteness area, and ABS Statistical Division. The results show a high level of consistency in average data rates achieved, as shown in the two charts below. Figure 3. Average cable download data rate by Remoteness Area - 5 -

7 For 512/128 kbit/s DSL, the Inner Regional averages were higher than Major Cities. This could be due to the larger numbers of subscribers in the cities causing some contention (blocking of shared resources) and hence slower performance. Figure 4. Average DSL (512 kbit/s) download data rate by Remoteness Area Note that results in a Remoteness Area do not imply that the broadband service is available throughout that area. It simply means that users from somewhere within that area had used the Line Speed Meter and generated test results. Overall however, the results show that regional customers are achieving performance levels that are not significantly different from city customers. Conclusions. The results of the Telco One study for the ACA indicate that broadband users are generally achieving a level of performance that is consistent with technical constraints of the Internet and the underlying broadband technology. It is important however, that the ACA and ISPs ensure that all consumers are aware of the differences between Plan rate and achieved rate. This report is the first of its kind by the ACA, and results will be tested and verified using other sources, including data requested from the ISPs. Even with such information being made available from ISPs, the ACA will consider the need for ongoing independent measurement of consumer experience. This is necessary due to the inherent factors that cannot be controlled by the ISPs, yet which contribute significantly to the overall consumer experience with broadband Quality of Service