Quarterly Report - DNS & Latency in August Quarter
Do all ISPs link to Australian cities directly?
Domain Name Server (DNS), and Latency Performance are important measures of internet performance. Our quarterly results show little change from last quarter, where Vodafone latency to Sydney, and 2Degrees latency to Melbourne are so large they may go via the USA to get to the peering exchanges we link to. These are important metrics, as a very large proportion of NZ traffic goes to and from Sydney, and Melbourne is a major centre in the region. Latency can and will impact small file downloads (eg websites), gaming, and potentially video or voice.
DNS Response Time
Quick DNS Response Times improve the internet browsing experience of users. Very slow DNS responses can cause timeouts, making the internet almost unusable. DNS problems often manifest as a slow response to changing websites or searching, while the responsiveness, or speed once on a page seems fine. DNS response is also affected by latency. Where ISPs have invested in distributed DNS's closer to customers, users will experience better DNS performance, all other things being equal. A DNS can also be overwhelmed by too many requests, again leading to very poor performance and incomplete searches.
We measure the time it takes to look up a website name (say truenet.nz) to identify the IP address that the Internet needs to know to find that site (in this case 22.214.171.124). For many websites, a DNS lookup is performed many times, for each part of the website, which can increase the time to download the webpage.
TrueNet measures the time taken to receive a response from all DNS servers that an ISP informs us they use (usually two). We then report the median of the best result overall for each hourly test recorded per ISP and technology. This is close to what happens when browsing a page on your computer.
Though there are few ISPs represented, DNS Response in the South Island has improved since the March report with South Island response times now roughly similar to those in the North Island. We report North and South Islands separately because DNS is very dependent on Latency which in turn depends on distance travelled. By investing in servers closer to their SI customers, ISPs can improve the performance of these customers.
The biggest differences appear to be in North Island ADSL response times. 2Degrees had the shortest response time at just over 10msec, contrasting with Vodafone, and Spark at almost 30msec. Fibre & VDSL do not appear to reflect such large differences. Vodafone Fibre has the shortest response time of all products at 4ms.Chart 1: DNS Response Time for the August 2016 Quarter
Latency is the time it takes for a packet of data to be returned by a remote server to a Panelist's probe. Latency is important to both responsiveness of the user interface, and also speed. Very high latency makes browsing the internet difficult, and may lead to timeouts.
Gamers are very keen to know which ISP has the best latency to the country, or location they use a lot - we have many requests to report this. High Latency can make gaming impossible, adding to reaction time, meaning that if someone else has lower latency they may see a game change, and react well before a slower connection is able to display the change (i.e. you can be shot, and killed in a game before your computer shows the shooter).
TrueNet measures latency to 6 test locations - Auckland, Wellington, Sydney, Melbourne, Dallas (USA), and the UK
Latency between Auckland and Wellington is almost exactly the same for all technologies apart from Cable. The distribution of panelists drives this difference, because the distribution of locations is similar for Fibre, ADSL and VDSL, but all Cable panelists are located in Wellington or Christchurch, so latency is longer for Auckland tests due to the difference in panelist locations. The odd result is that of Spark Fibre in the South, which shows greater latency to Wellington compared to Auckland, suggesting Wellington is electronically further than Auckland from the majority of panelists. This result is also worse than Spark's North Island VDSL, although we currently do not have enough Spark panelists in the SI for DSL comparisons. (Volunteers are being recruited now, we expect to return to publishing all 4 main ISPs next quarter)
Chart 2 shows the latency to Auckland and Wellington from FIbre & Cable connections with a service speeds of 50Mb/s to 200Mb/s where the faster technologies of Cable and Fibre have the best latency to their local server - with an average for the entire country of 10-13msChart 2: Fibre & Cable NZ Latency for August 2016 Quarter
The next chart has VDSL latency to Auckland and Wellington. Orcon and 2Degrees stand out in the North Island with lower latency to AucklandChart 3: VDSL NZ Latency for August 2016 Quarter
ADSL Latency shows 2Dgrees standing out.Chart 4: ADSL NZ Latency for August 2016 Quarter
Last quarter TrueNet's latency report in March showed that Trustpower & MyRepublic had increased latency at peak hour. Since that time the evening latency of both ISPs has improved a lot. Please see charts 5a for August, and compare with the March chart in 5b. All other ISPs have ceased measurable Time-of-Day variations. These charts cover all technologies, with Trustpower & MyRepublic having predominantly fibre panelists, which has an impact on the overall latency, but the variation is expected to be independent of technology.
|Chart 5a: Auckland ToD August '16 Quarter|
Chart 5b: Auckland ToD the previous March '16 Quarter
USA & UK Latency
|Measurements are made to Dallas in the USA, and Portsmouth in the UK. Both locations are several thousand km's away over fibre, increasing the time it takes for signals to traverse the cables.|
The significant extra distance to the USA & UK leads to the much higher latency in Chart 6. The results are generally similar to those from March, but the greater latency in Vodafone UK results in March has been resolved, and they now are similar to other ISPs reported in the chart.Chart 6: USA & UK Fibre & Cable Latency for August 2016 Quarter
Technology has litte impact on latency over long distances so ADSL and VDSL results look remarkably similar to FibreChart 7: USA & UK VDSL Latency for August 2016 Quarter
Chart 8: USA & UK ADSL Latency for August 2016 Quarter
|TrueNet measures latency to servers in Sydney and Melbourne. International capacity between NZ and Australia appears to pass through Sydney, so there is an expectation that Melbourne latency should be greater, all other things being equal. The only cable out of NZ leaves via Auckland, so South Island latency is also greater than North Island.|
The Australia latency performance chart continues to show Vodafone and 2Degrees fibre with higher latency to Sydney and Melbourne respectively. This pattern remains the same as in the March report.Chart 9: Australia Fibre & Cable Latency for August 2016 Quarter
Again VDSL and ADSL trends to Sydney and Melbourne are the same as Fibre.Chart 10: Australia VDSL Latency for August 2016 Quarter
Chart 11: Australia ADSL Latency for August 2016 Quarter