ADSL problems caused by new Telkom system: ISPs

Telkom has rolled out a new dynamic spectrum management system (DSMS) that is designed to automatically administer ADSL services – ensuring they run at their maximum possible speed while remaining stable.

The system was developed by US-based broadband network solutions provider Assia, and Telkom said it has been progressively implemented on its network since 1 October 2014.

“The system is designed to dynamically analyse line statistics such as signal to noise ratio, attenuation (resistance to signal), and sync stability and then reset the line profile for the best performance for each individual line,” a spokesperson for Afrihost said.

Afrihost said when the full interface is available, they are told it will make front-line support more effective and also help with fault logging.

“It will also minimise the possibility of human error in fault diagnosis, saving the client’s both time and money.”

ISP tech support “crippled”

Although the DSMS promises to reduce the number of faults reported and provide clear fault diagnostics, ISPs say it has had the opposite effect.

“We’ve noted a distinct increase in the number of line faults we’ve had to log for customers since the system was brought online,” said Ettiene Cloete, MWEB’s general manager of operations.

One user said when the change-over to the Assia system happened in KwaZulu-Natal, his local latency went from 16ms to 30ms and he experienced packet loss.

“I have noticed that [connections to my service provider] now drop randomly for a few minutes at a time regardless of ISP used, however my line stays synced perfectly. I had better line stats before Assia was pushed out,” the user said.

Cloete explained that MWEB’s ability to assist with lines that are in a “marginal state” due to poor cable quality, distance from the exchange, and other factors has been crippled as their support staff can no longer manually stabilise a line at a particular speed.

He said this may be due to the frequency at which the system triggers port optimisation events, which cause the line to be in an unstable state until completed.

Load shedding, VDSL issues

MWEB has also noted problems with VDSL-capable devices, such as its Fon router, where the optimisation process fails and leaves the service in an unusable state.

“We believe this deployment has been complicated by environmental factors such as Eskom load shedding and the fact that it coincides with the constant, intrusive maintenance work taking place due to Telkom’s ongoing [next-generation network] rollouts,” Cloete said.

He said there is evidence to suggest that port optimisation is being triggered on a large scale after power is restored on ADSL services after load shedding.

Asked about this, Telkom’s Jacqui O’Sullivan said that power outages have no impact on the DSMS.

“Events relating to load shedding are collected by the DSMS but the optimisation process is not triggered by this event data,” O’Sullivan said.

“Telkom is not aware of any conditions under which load shedding would leave a port in a state where a reset is required.”

The rollout of its next-generation fibre and VDSL-capable network also has no impact on the DSMS, Telkom said.

Telkom MSAN installation

ISPs didn’t fix users’ actual ADSL problems

Asked about running the old management system in parallel with the new DSMS, Telkom said it wants to prevent ISPs “manually stabilising a line at a particular speed” as MWEB described earlier.

“The previous method of fault-handling enabled ISPs to stabilise customers’ services by lowering the speed-profile,” O’Sullivan said. “This provided a quick fix to faults without addressing the actual problem.”

Telkom said the old fault-handling method has been disabled as it interrupts the DSMS system, and prevents it from dynamically managing services.

It added that only the ability to change speed profiles and modulation types has been disabled.

“The ability to perform port resets is still available to ISPs. The existing diagnostics and fault reporting functions are still in place and have not been replaced or disabled.”

Telkom has promised ISPs, such as Afrihost and MWEB, additional diagnostic and troubleshooting tools, which will allow them to provide better first-line technical support.

“The DSMS will, after careful analysis of the DSL line, provide ISPs with possible actions that can be used to resolve their customers’ queries,” Telkom said.

Good idea, bad in practice

Both MWEB and Afrihost were positive about the concept of an automated management system such as the Assia solution.

“There’s no question that deploying next-generation fault detection and service management systems is a good idea,” Cloete said.

However, MWEB went on to argue that a new system like the Assia DSMS is of little value if they are not given direct access to the port management and fault detection capabilities such a system can provide.

Afrihost added that the most important aspect will be the follow-up support from Telkom’s technical team.

“If that is it in place and continues to improve due to a more streamlined system, then we believe this is a step in the right direction.”

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