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ASSIA court case forces Openreach to turn off DLM
Wednesday 26 November 2014 09:58:48 by Andrew Ferguson

After a few years of getting PR emails expounding the virtues of DLM systems around the world that ASSIA have provided a court case has seen BT found to be infringing two ASSIA patents with its NGA DLM system.

"For several years, British Telecom has used a system called “RAMBo,” which is short for Rate Adaptive Management Box, to provide Dynamic Line Management (“DLM”) to optimize broadband speeds for its DSL broadband services. The “BT Infinity” superfast broadband service is provided on BT’s Next Generation Access (NGA) network. UK courts found that the DLM system used to manage BT’s NGA network infringes two patents owned by ASSIA, Inc., a leading provider of software solutions for broadband access networks. The courts ruled that BT would have to stop using the NGA-DLM system or pay ASSIA £250,000 per week until the system is modified to make it non-infringing. ASSIA has been notified that BT discontinued use of the NGA-DLM on Friday, 21 November. ASSIA believes that this action will have a negative impact on BT customers’ quality of service and speeds."

Extract from ASSIA press release

The presumption we are making is that the removal of the DLM refers to JUST the Openreach FTTC based services and will thus affect all providers, not just Infinity. The wording NGA-DLM is a bit confusing since in some circles WBC ADSL2+ is called NGA, and an enquiry has gone out to BT to confirm which system has been turned off.

Paying the penalty while continuing to run the system would be the same as NOT installing another five or six fibre cabinets, or the equivalent of adding around 30p per month to every FTTC connection (remember that the wholesale price is £8 to £10 per month).

While ASSIA is keen to say that turning off the service will lead to a degradation of service, it is very much an unknown as to how many will be affected. There is a school of thought too that the DLM is often too harsh and increases interleaving or descreases speeds too much, so while some may see their line start to flap around more, others may see speeds improve at the expense of the occasional re-sync. The main aim of any DLM system is to avoid a line trying to sync at a high speed and then re-syncing two minutes latter, i.e. flapping about.

An interesting aspect is that it looks like Sky or TalkTalk use the ASSIA DLM system as the report talks of five million lines using the system in the UK, which has to be referring to ADSL2+. For now BT is either working furiously to create a new DLM system and avoid the penalty or will end up buying the ASSIA system, or we might discover that the problems are small enough that giving providers manual control for speed capping may be enough.

Update 27th November 2014: We have received a statement from BT which is reproduced in full below, and tells a slightly different story to the ASSIA release.

"BT has been defending a claim brought by ASSIA since November 2011. They had asserted three patents against BT but during the proceedings, they had to narrow their allegations and withdraw one of these patents entirely.

In January 2014, the High Court found BT was infringing on only a minor part of one patent, and the Court of Appeal, whilst invalidating the majority of the claims of ASSIA's other patent, ruled that BT's network infringes what remains of the other patent.

Although BT was disappointed with the ruling, we have made minor changes to our programming which means these two decisions have no material effect on the operation or performance of our networks."

BT Statement on DLM ruling


Posted by joe_pineapples over 2 years ago
I wish Sky would give ALL customers the choice of having their line 'managed' or not, the way the 'PRO' customers can. I could have my old 10meg back instead of the 8 I'm currently getting, and would be quite happy to endure the odd resync.
Posted by adslmax over 2 years ago
Why is openreach keeping it quiet? Are FTTC DLM is finally switched off for good?
Posted by dogbark over 2 years ago
Is this April Fools or Christmas?
Posted by balb0wa1973 over 2 years ago
The dlm system is a pain in the arse, id rather have no interleaving and a few re-syncs a day than a stable line for 10 days and 16ms of interleaving.

My interleaving is still on!!! get it off!
Posted by balb0wa1973 over 2 years ago
Everyone just wants an option, on or off, we have been waiting years for it.
Posted by adslmax over 2 years ago
Look like DLM isn't switched off? BT is lied again.
Posted by andrew (Favicon staff member) over 2 years ago
It may be that lines are still running with the settings learnt, but the decision making DLM part is turned off, ie. might be stuck with the decision made before 21/11
Posted by Ixel over 2 years ago
I can see lots of people complaining to BT eventually about a stuck DLM profile and demanding a reset - ha, I bet mine is going to remain stuck.

Good news and bad news possibly.
Posted by adslmax over 2 years ago
If BT switched off DLM on 21st November - then why aren't BT reset all DLM by default? As the ISP's cannot reset DLM, only the Openreachj can do this.
Posted by mervl over 2 years ago
Interesting. My FTTC latency has been over 20ms for years, occasionally (usually summer)halves but not for more than two days. Since late last week it's stuck at below 10ms, with no noticeable effect on the connection. Interleaving off for the first time. And it's wet (old underground line). May have changed prior to 21st though.
Posted by adslmax over 2 years ago
I do hope that ASSIA will tell BT Openreach to turn off stupid IP Profile as well.
Posted by balb0wa1973 over 2 years ago
just reset my modem, still on 16ms interleaving fttc. So have BT stuck the profiles then? pffft
Posted by andrew (Favicon staff member) over 2 years ago
On FTTC IP Profile is a non issue, you cannot remove the protocol overheads which is all the IP Profile covers on FTTC.
Posted by mdar5 over 2 years ago
So ASSIA complain about BT using it.
BT tell them OK we will stop ...and no we are not prepared to meet your outrageous demands for payment.
ASSIA then complain that now their system is not being used users will see a reduction in performance and ASSIA are terribly upset about this.

Presumably ASSIA thought all along BT would pay and are now in a mess.

Posted by adslmax over 2 years ago
@ andrew f : Can you please ask openreach does turn off DLM mean it will auto reset the DLM itself? It seem that DLM turned off haven't working well with interleaved still ON.
Posted by Ixel over 2 years ago
@adslmax : Yeah I agree. It would be fantastic if they did eventually reset everyone's profile, or made it possible to request a profile reset without an engineer callout (e.g. via a form or contact number on their website, or even via the ISP).
Posted by andrew (Favicon staff member) over 2 years ago
Already have enquiries underway to confirm whether this is JUST FTTC or includes WBC too.
Posted by balb0wa1973 over 2 years ago
i thought this was brilliant news at first, then i realised, if anyone has interleaving on their line, it wont come off now will it.
Posted by Ixel over 2 years ago
The only other alternative is to re-grade. That meaning go from 80/20 to 40/10, then back to 80/20. I imagine changing package speed resets it. Unfortunately I'm not sure how many ISP's would do that, and I also believe there's a small fee to re-grade. If Zen were able to do that I'd be prepared to pay a small fee (depending how much it would be).
Posted by adslmax over 2 years ago
Plusnet had confirmed it had no information if DLM turned off or reset the DLM by default. Back in the dark again. We won't know if the DLM still active or inactive?
Posted by chrysalis over 2 years ago
Time to flood feedback lines and say service improved since 21 november :)
Posted by themanstan over 2 years ago
Has anyone rebooted their router to see what happens?
Posted by balb0wa1973 over 2 years ago
yes i rebooted, still on 16ms interleaving, and my upstream snr is 19db still, its been stuck on that for over a year, pathetic.
Posted by balb0wa1973 over 2 years ago
profiles will be stuck now it seems, only a reset by openreach will sort it. questions need to be asked by the isp's
Posted by adslmax over 2 years ago
DLM doesnt actually set the interleaving parameters, the DSLAM does, DLM just tells the DSLAM what to do, meaning BT can and probably will maintain all existing profiles, just they will currently not be automated changes.
Posted by adslmax over 2 years ago
Beware of BT will going to try new DLM v2 next year! lol
Posted by gordslater over 2 years ago

My best defense against DLM craziness and a lot of other ISP frustration was to change ISP to A&A ( AAISP / Andrews and Arnold) They have so many line tweakables on their web control pages that you can usually select your preferred speed/noise/margin action on any given lines depending on your requirements - max speed / less reliable when it's noisy OR slower speed / reliable when it's noisy. You can generally see the differences within 24-48 hours on their line quality monitoring graphs as patterns emerge. A&A aren't cheap but quality costs - pay peanuts, get monkeys

Posted by stephentodd over 2 years ago
We just had a long and noisy power brownout and two power cuts, exactly what might have upset DML in the past. I am now syncing at higher sync speed(74000->79000) and lower SNR speed (6.3->5.1) than before, and still not interleaved. Don't know if that helps anyone guess better what the current state of DLM/profiles is. Probably any resync settings came from my very stable state before, so I've come out on the lucky side of the new setup.
Posted by TheEulerID over 2 years ago

It would be fairly easy to allow user to tweak settings. That's not the problem. The real issue is one of the sophistication (or otherwise) of the customer base, the consequent avalanche of calls that are likely to flood help desks.
A simpler version could be developed whereby customers set relative priorities (e.g. speed, stability and latency) with defaults. Also, some mechanism to limit numbers of changes to avoid swamping management interfaces.
Posted by otester over 2 years ago
Got to give them credit for being the first patent troll with a suitable name... ASSia.
Posted by WWWombat over 2 years ago
LOL @otester

Ironic that the UK doesn't allow software patents.

Speaking as one skilled in the art, isn't a state machine one of the fundamental design data structures of real-time & hardware control programming?

Exactly how Assia's patent managed to get over the hurdle of being novel, while also not being software, is a secret known only to patent clerks.
Posted by WWWombat over 2 years ago

Reading further, it seems that BT believes it has already fixed DLM so that it no longer contravenes one of the patents, and has asked the court to decide if the amendment does indeed remove liability.

The court hasn't yet decided on that aspect.

However, they did decide that BT should pay the weekly sum to Assia for continuing to run DLM, while they make up their minds!

Successful trolling indeed!
Posted by ChrisAO over 2 years ago
IIRC it is currently not possible to tweak FTTC settings remotely, an engineer has to go to the Cab. Remote tweaking only applies to WBC.
The idea of regrading twice would not involve a "small" fee with engineers having to goto a Cab, Ixel. Quite the reverse.
It's not possible to get rid of an IP Profile as Andrew has mentioned, there are headers in data packets, that's the way everything works. I do wish you'd go and learn how DSL works before making some of your ridiculous suggestions.
Posted by Ixel over 2 years ago
@ChrisAO: I think you may have misunderstood me. I'm not referring to the engineer having to do the regrade (I thought the ISP would need to submit an order to wholesale?), I was referring to wholesale or whoever's responsible for the order. I thought I read somewhere that wholesale charge a fee for regrading.
Posted by Blackmamba over 2 years ago
Hi broadband Watchers
My understand of the DLM is that it checks the line on provision then after 48 hours it locks the profile then continues to monitor the line for Interferance and changes when a problem is monitored. So by removing it you are adding to the errors this will extend the time on the data transfer.
Posted by phil_w_lee over 2 years ago
Mayby BT should counterclaim against ASSia, for use of the programmable digital electronic computers in developing their DLM, which as any reader of history will know, were invented by a BT (then part of the Post Office) engineer, Tommy Flowers, at Dollis Hill and installed at Bletchley Park from 1943 onwards.
Lets see, what would the backdated royalties on that be?
Posted by Blackmamba over 2 years ago
Hi Broadband Watchers
Last week my down speed was aprox 34 the last two days 18 and 9 up it looks like the outside lane has been closed.
Posted by Blackmamba over 2 years ago
Hi Broadband Watchers
Could it be they are going to provide vectoring on Cabs in this Q4.
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