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Plusnet Usergroup » All Users - The Open Forum » Announcements » New LLU FAQ Posted
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Author Topic: New LLU FAQ Posted  (Read 19125 times)
biondani

Posts: 2223

« on: July 29, 2006, 10:26:43 am »

Please see here for details of the new LLU FAQ: http://usergroup.plus.net/news_newllufaq.php

Ian

3rd Line Wintel Support
Virgin Media XXL Customer
Oldjim

Posts: 1014

« Reply #1 on: July 29, 2006, 11:01:39 am »

A couple of questions.
what is the significance of
Quote
We provision customers against a business grade product when they are moved to Tiscali
Can you clarify this 
Quote
What does the 'stable rate' figure on the portal mean with respect to an LLU line?
    The stable rate figure refers to the maximum speed allowed at our end. For all customers on the Tiscali platform, this should be 8000kbps.
It was previously stated that the Stable Rate provided by BT was needed to reduce packet loss as it would stop the PlusNet system pushing data at the customer faster than it could be accepted. Will this have the effect of inflating the usage numbers as reported by the Ellacoyas.
LC100

Posts: 283

« Reply #2 on: July 29, 2006, 11:36:06 am »

Hi

I have raised these comments over at ADSLGuide and bring them hear as PlusNet do not frequent there anymore and this is the prefered communication point.

Quote
no PAYG customers are currently being transferred to LLU.

Well I'm on PAYG and was transferred and suffered 11 days down time because of it. Maybe the "currently" means as of this minute but we have before and may again!  This has been picked up from ADSLGuide and fed back to PUG to check.

Quote
MTU 1458

Testing has shown by me and others that MTU is 1440.  I have just tested again using an MTU of 1458 and visited http://www.speedguide.net:8080/ and MTU is 1440, so from what I understand using MTU of 1458 is causing an overhead as the packets need to be fragmented somewhere on Tiscali's network, so a value of 1440 should be the correct one?

Quote
Can I connect with ADSL2/2+ equipment (and get upto 24 Mb speeds)? If so will I be capped to 8Mbps?
Tiscali will provide ADSL2+ connections when the number of our customers on any exchange exceeds a given threshold (This ranges from exchange to exchange).

If you have an ADSL 2+ capable device, you will still be able to use this to connect to a non ADSL 2+ exchange. Once the exchange has been upgraded, the speed you receive will depend on the quality of your line and the product you have with us. You won't be capped if you are on an upto 24Mb product.

I can connect to the exchange using ADSL2+ but capped at 8000, the FAQ seems to imply that if you connect with ADSL2+ that is because the exchange has meet some target and upto 24Mb is available if your product supports it.

My question, as a PAYG customer (that shouldn't be on LLU at all it seems so they may not have an answer) should I get the benefit of >8Mb on that product? I would have thought yes, as on PAYG if we use more, we pay more so PlusNet are happy with some more cash coming in.

Other than that good to get some clarification at last on no BRAS etc, and how the line profiles are set up.  Of course this would have been even better if provided at the start of the LLU migration rather than later when we had worked a lot of it out for ourselves, but better late than never and will help others new to LLU Smiley



« Last Edit: July 29, 2006, 11:38:24 am by LC100 »
Ultra

Posts: 777

WWW
« Reply #3 on: July 29, 2006, 12:45:32 pm »

Maybe it should read that ADSL 2+ with support for speeds above 8000 will depend on the number of users at the exchange meeting some (unspecified) threshold for Tiscali. 

I don't even know how one detects it is an ADSL 2+ connection (reported by the router, I assume!) but I remember seeing the list of "up to 24 Mbps" for PAYG users be downgraded later on (perhaps to avoid any "but the product was described as ..." complaints in future Smiley )
LC100

Posts: 283

« Reply #4 on: July 29, 2006, 01:13:48 pm »

Hi

Quote
Maybe it should read that ADSL 2+ with support for speeds above 8000 will depend on the number of users at the exchange meeting some (unspecified) threshold for Tiscali.

Yes quite likely.  Typical though that a FAQ from PlusNet is not clear and is raising more questions to get the answers clarified!
Kritifile

Posts: 238

WWW
« Reply #5 on: July 29, 2006, 11:13:57 pm »

Fistly, the MTU. Through experimentation I found that 1458 was best for BT MaxDSL.
So maybe that has got mixed up and it should be 1440?

Can somebody on LLU test to find the ideal packet size, as that will help users avoid fragmentation.

Now, my mail concern is the 12 dB SNR and the interleaving. This is fine for people with good lines, but what about the rest?

For example, although my line-of-site to the exchange is only 1.8 km, I have attenuation of at least 58 dB, it was up to 63 dB until I bought a wireless router and used a very short cable. With 6 dB attenuation and fast path I can sync at up to just over 4000 kb/s, and I have a stable connection with a 6 dB profile, although part of the reason for that is a router that can hold the line down to 1 dB. With a 12 dB SNR and interleaving my sped is going to drop, I don't know how much by, but probably I'll be lucky to get 2000 kb/s.

My exchange, I believe, is due to be Tiscalli-LLU enabled next month. I'd be happy to lose the BRAs profile, because that, plus exchange contention, reduces my speed. But as things are now, it seems that I'll have a slower conection.

I have a question for PlusNet. Can a customer who knows that their line is stable on a lower SNR profile have it set to lower SNR by Tiscalli in advance, so that the line is provisioned with that profile and is only increased if it becomes unstable?
If not, how long does one have to waiyt on slow speeds before being able to ask for an SNR reduction, and will it be possible to obtain it?
Secondly, interleaving also reduces speed, which is of interest to all those on long and poor quality lines. I know that companies that turn on interleaving by default do so to reduce connection problems, but can PlusNet request the ability to turn interleaving off for those who have never had, or needed it to be applied, as a matter of urgency?
LC100

Posts: 283

« Reply #6 on: July 30, 2006, 09:54:59 am »

Hi

Quote
Can somebody on LLU test to find the ideal packet size

1440 is the best number, anything above this is fragmented somewhere on Tiscali's network to 1440 anyway.  Download speeds seem to average slightly better on 1440 than any other setting.

Quote
Now, my mail concern is the 12 dB SNR and the interleaving. This is fine for people with good lines, but what about the rest?

For me this would have caused some dissatisfaction.  With DSLMax I was happily getting 8128 (the maximum sync) on my line, which was completely stable, but with Tiscali's 12db SNR I can only sync to around 6500-7000, plus have interleaving on.  It is only due to being able to sync now with ADSL2+ that allows me to get the full 8000.

The FAQ mentions LLU lines are more stable for this higher SNR than MaxDSL and of course that will be true, although other problems have dogged LLU.  The fact we don't have all this 3 day knock back for BRAS and it doesn't matter how many times we sync (whether that's testing, a fault or thunderstorms causing it) there are no fears of the exchange equipment suddenly deciding to up SNR even more.

I think the LLU way is the better way as DSLMax automatic systems don't really work, however the LLU way should allow users to reduce or increase SNR easily so they can achieve the maximum the line allows like DSLMax.

Quote
If not, how long does one have to waiyt on slow speeds before being able to ask for an SNR reduction, and will it be possible to obtain it?

It seems PlusNet will get some tools for this and we will be able to request it and it would be nice if these settings were available via the portal.  If we have to raise a ticket for these settings to be changed I expect few if any front-line will know about it and ticket tennis for a few games will be required to get anywhere, as per usual!

Quote
Secondly, interleaving also reduces speed, which is of interest to all those on long and poor quality lines. I know that companies that turn on interleaving by default do so to reduce connection problems, but can PlusNet request the ability to turn interleaving off for those who have never had, or needed it to be applied, as a matter of urgency?

The interleave setting isn't as deep as the setting DSLMax use so has less of an impact on the line.  The FAQ does mention that they are looking into a user being able to request to turn it on and off.
mr_chris

Posts: 1927


« Reply #7 on: July 30, 2006, 11:40:49 am »

Thanks for that insight Smiley

Chris
Kritifile

Posts: 238

WWW
« Reply #8 on: July 30, 2006, 12:16:10 pm »

Thanks for the info on LLU.

I have a nice stable DSLMax connection, only  losing sync to increase sync speed, never the other way. But with a target SNR of 6 dB, I often get as low as 3 dB, in fact I'm running on that half the time.

So the only way I'll  find out if the doubling of SNR, plus interleaving, on a line that's never needed it, is to wait and see.

On Samknows one link says my exchange isn't Tiscalli-enabled, another says it is. But a neighbour with Tiscalli retail has been informed that they'll be putting ADSL2+ equipment in sometime in August, so I shouldn't have long to wait.
Especially as I just about manage to avoid management of my account each month since the new VMBU plus my Max upgrade happened.
morrisinc

Posts: 109

« Reply #9 on: July 30, 2006, 05:42:54 pm »


Quote
It seems PlusNet will get some tools for this and we will be able to request it and it would be nice if these settings were available via the portal.  If we have to raise a ticket for these settings to be changed I expect few if any front-line will know about it and ticket tennis for a few games will be required to get anywhere, as per usual!

I'm currently going thourgh this at the moment.  The 12db SNR is pain - my line on BTMaxDSL was 5800 to 6200 sync @ 6db.   Now on LLU 12db SNR - sync is 4200 to 4800.  Also Interleavel too.

But on the good side from BT - not much contension effect at peak times now - did start to notice it on BT.  Also I believe Tiscali's backhaul is IP not ATM on BT - less overhead - means even with the lower sync rate my TCP speed is about the same as it was on the faster sync BT.

Phil
mr_chris

Posts: 1927


« Reply #10 on: July 31, 2006, 12:21:33 am »

> I believe Tiscali's backhaul is IP not ATM on BT - less overhead - means even with the lower sync rate my TCP speed is about the same as it was on the faster sync BT.

Not quite - your connection is always ATM from the router to the exchange, therefore your TCP speed is always going to be ~10-15% lower than your sync speed. Period.

You are possibly noticing that the speed is relatively faster because (a) Tiscali is less congested than BT at the moment. and possibly (b) your SNR margin is higher and Interleaving is meaning fewer uncorrected errors occurring?

Chris
morrisinc

Posts: 109

« Reply #11 on: July 31, 2006, 06:26:53 am »

Hi Chris

Silly me  embarassed your right that - thats what the A in PPPoA is - ATM.

I think maybe A) less congestion.  As I could get higher TCP speed when I was sync-ed @6200 (got 5.5mb profile)  Maybe as Tiscali as not profile BRAS thingy this helps too?

Phil
thepuffin

Posts: 116

« Reply #12 on: July 31, 2006, 10:50:16 am »

Very nicely put together FAQ and answers all the questions I had when my connection was moved last week.

Any chance we could get the CSC to read it as they're still telling LLU customers that they have MaxDSL and BRAS profiles.
ianwild

Posts: 3979


Not to be confused with Mike, Wildmind.

WWW
« Reply #13 on: July 31, 2006, 12:00:46 pm »

smiley ... I will make sure all of this is re-itereated, and if we see examples of incorrect information, a ticket number allows me to raise these straight to the managers of the people concerned. We are looking to put together some additional training sessions for the guys too.


Of course, I was never going to be able to answer everything, and it's alwasy a shame when we don't!

- The MTU info came from Tiscali. I remember a similar thing happening with BT when customers were experimenting with this. PUG now have control of the FAQ and if we can update the question answer to talk about using other MTU values, that might be an idea. When we put this on the portal we will use the most up-to-date content from the PUG version.

- In terms of PAYG users being moved, I appreciate the example, and the products guys are looking into this now with the Database guys who generate the criteria lists. Obviously it has happened and I'm sorry that the FAQ information conflicted with that. I have certainly confirmed that PAYG users are not expected to be moved to LLU at this stage (And while I'm covering my back there by saying that, we don't expect that to change).

Quote
I have a question for PlusNet. Can a customer who knows that their line is stable on a lower SNR profile have it set to lower SNR by Tiscalli in advance, so that the line is provisioned with that profile and is only increased if it becomes unstable?
If not, how long does one have to waiyt on slow speeds before being able to ask for an SNR reduction, and will it be possible to obtain it?
Secondly, interleaving also reduces speed, which is of interest to all those on long and poor quality lines. I know that companies that turn on interleaving by default do so to reduce connection problems, but can PlusNet request the ability to turn interleaving off for those who have never had, or needed it to be applied, as a matter of urgency?

We can't request the settings changes in advance, but the impression I get is that changing the SNR takes about 5 days currently from the time we request it. Interleaving is about the same, and I'vve checked that we can switch it off. Some of these items are new for us now and we are still pushing the boundaries and building the relationships with Tiscali. I would say in a months time things will be a lot clearer on these fronts.

As someone participating in the PUG forums, you always make a good test case though, so myself and James would be happy to help you through any of those changes in return for some feedback about what works best.

Quote
Maybe it should read that ADSL 2+ with support for speeds above 8000 will depend on the number of users at the exchange meeting some (unspecified) threshold for Tiscali.

The threshold is between 100 and 150 users per exchange. It does seem worth the FAQ being updated to make this a little clearer. Again, if PUG can make the changes on the public FAQ we can make sure they get replicated when we publish the FAQ later this week.

Have I missed any other questions?

Ian

Regards,

Ian Wild
PlusNet Support
Colin
Usergroup Member

Posts: 6339


WWW
« Reply #14 on: July 31, 2006, 04:44:07 pm »

Again, if PUG can make the changes on the public FAQ we can make sure they get replicated when we publish the FAQ later this week.

If there's a clear list of changes required, we can.

Colin Ogilvie
Plusnet Usergroup Member
Using: Plusnet Extra
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