Telkom ADSL performance indicators
On 17 August 2006 ICASA published its Regulations regarding the provision of Asymmetric Digital Subscriber Line (ADSL) services.
These regulations require Telkom, SNO [Neotel] and Internet Service Providers (ISPs) to publish on their website, on a quarterly basis, Key Performance Indicators (KPI) of at least packet loss, average latency and jitter for the provisioned ADSL service. The regulations further require the quarterly publication of contention ratios associated with the ADSL service.
It is difficult to find any ISPs which adhere to these regulations. While a few large ISPs like WebAfrica have some information about the contention ratio of some of the ADSL services which they resell, others like MWEB and Internet Solutions carry no easily accessible information regarding key performance indicators or contention ratios associated with their ADSL offerings.
Many ISPs will argue that they are merely reselling an ADSL services from Telkom, Internet Solutions or MTN to consumers, and therefore have no control over the contention ratio or key performance indicators associated with their ADSL offering.
The ADSL Regulations however do not appear to provide these ISPs with exemption from publishing this information on their websites, and they may well be in breach of the regulations.
Telkom ADSL performance indicators
Telkom has updated their website with key performance indicators and contention ratios since July 2007, but still falls short of the requirements set out in the ADSL regulations.
Telkom has thus far published 5 sets of performance indicators since the ADSL regulations were gazetted on 17 August 2006, well short of the 10 sets which equates to quarterly publications of KPIs.
According to the Telkom website the contention ratio for their ADSL service is 20:1. “Contention ratios are an international norm and all ISP’s make use of it. The contention ratio does not remain constant as it fluctuates as the service grows and more customers and infrastructure are added,” the Telkom website adds.
Telkom’s latest set of ADSL KPIs, for July to September 2008, are as follows:
- An average international package loss of 0.14% and a maximum international packet loss of 95%
- An average international latency of 279 ms and a maximum international latency of 3285 ms
- An average international jitter of 3.27
- An average local package loss of 0.20% and a maximum local packet loss of 66.11%
- An average local latency of 21 ms and a maximum local latency of 1277 ms
- An average local jitter of 23.14
Dubious results
There are however inaccuracies in the latest Telkom KPIs which cast a shadow of doubt on the overall accuracy of the results.
According to Telkom’s July – September 2008 Performance Indicators the maximum packet loss percentage to all five destinations which were measured, namely Amsterdam, Ashburn, Hong Kong, London and New York, were all 95%. While it is not impossible, it is highly unlikely that the packet loss in all cases would be exactly the same.
A more worrying result from Telkom’s KPI results is that it gives three of its five minimum international latency results as 0.00 ms. These results are then used to calculate the average minimum international latency which is given as 74.56 ms – clearly a mistake.
The same inaccurate results are provided for local latency where three values are given as 0.00 ms and the average minimum local latency is 1.89 ms. Well known networking expert and Neology CTO Roelf Diedericks said that the results are “clearly inaccurate and defies the laws of physics”.
Diedericks calls the minimum latency results of 0.00 ms ‘completely incomprehensible’. “No ESR will ever have 0ms latency from a customers’ perspective. The DSL protocol simply has more inherent latency than that.”
Diedericks suggests that there might be a flaw in Telkom’s monitoring scripts, and that it would probably be a good idea, for the sake of transparency, if Telkom publicizes the mechanisms and locations for measurement.
Diedericks however congratulated Telkom for adhering to the ADSL Regulations in publishing KPIs. “Telkom should be lauded for their efforts in publishing KPIs across a complex network. Other commercial operators would be hard pressed to comply with these requirements,” Diedericks concluded.
Telkom ADSL performance discussion
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