100M : Small Download Speed Upgrade

[AndyCalling]

Originally Posted by Ignitionnet

The key components of Virgin's problems right now are the number of customers per segment (too many) and the traffic management on 100Mb specifically (none).

This has always been my puzzle. To my mind, if you need to control the usage of the top 5% of capacity users, the declared goal of the system, then the current system of speed curbing in traffic management is weird. My reasoning is as follows:

The top 5% of capacity users are almost certainly going to be on the top tier service (currently 100meg).

To catch the top 5%, a suitable usage limit should be placed on top tier and when exceeded their speed is limited much like the current system on the lower tiers. Similar for upstream.

That should catch the top 5% of capacity users. The same limits should be placed on other tiers to prevent that top 5% from moving to 50meg services and sacrificing speed for unlimited capacity. Standard lower tier users will never get close to these limits though, as they would be designed for the 100meg service, and so the lower tiers would effecitvely have no limits to worry about.

Currently the top 5% get away scot free leaving the lower tier customers to get restricted so as to open up capacity for those top 5% to gobble up. This is the reverse of the stated purpose of the policy and such a policy is not going to be viable once Youview gets hold.

Clearly it needs addressing. Let's hope someone is actually thinking things through logically. I have no speed issues but I fear the day they will happen and am keen to see a logical policy put in place that actually targets the top 5% instead of missing them completely and restricting everyone but the top 5%.

[Daveoc64]

Originally Posted by AndyCalling

top 5% of capacity users

IMO this was merely an excuse to cover up for serious underinvestment in parts of the network (*cough* Telewest *cough*)

[AndyCalling]

Originally Posted by Daveoc64

IMO this was merely an excuse to cover up for serious underinvestment in parts of the network (*cough* Telewest *cough*)

Whether the 5% figure is accurate or not, the only reason to control usage is to relieve pressure on the network and the only sensible way to do that is to deal with the top percentage of users. Otherwise, there is no reason to have a policy at all. Until the percentage targetted is updated by VM we can only work with the info we have when assessing the success of the policy in place and the approach to reforming it.

Whatever that percentage is though, my point is still valid.

[Chrysalis]

Originally Posted by roughbeast

Now that's a question I always wanted the answer to Chrysalis. I wonder if Ignition has the answer.

Did I do good?

-----------------------------------------------------------------------

However I think I understand Ignition's response better than your follow-up question. To me a key point is that it is inevitable that 1 out of 10 people on a 10Mb pipe will at some point use up 10% (1mb) of the capacity. It must happen all the time! To use up 10% (10Mb) of a 100Mb pipe with a 100 users in it is more difficult. It requires 10 of those 100 users to be simultaneously using 1Mb of capacity. That will probably happen quite often, but not inevitably. For the other 90 users to be using the other 90Mb simultaneously is very unlikely, much less likely than the other 9 users using the remaining 9mb of a 10Mb pipe.

You asserted that Ignition said that smaller nodes were better. I didn't catch him saying that in this context so I don't know if he is being contradictory.

Your question about merging 4 segments so more customers have more space sounds sensible. 10 users within 8x18Mb channels sounds less advantageous than 40 using 32x18Mb channels.

I bet there is an engineering obstacle to this. I can't believe it hasn't occurred to VM.

BTW the 10 or so 200Mb trialists in Coventry were on a 1Gb pipe. A 10Gb pipe was held in reserve, but was never needed.

Well he said they had too many users per segment, so by that I assume he means the node sizes need to be reduced as realistically the only way to reduce the users is either to move some to another segment, or split the node into smaller nodes. If there is a 3rd way someone is welcome to tell me.

So the way I see it if VM are to reduce node sizes in an attempt to support higher speeds then its logical to have those nodes still as one but with the extra capacity instead.

Do you agree its less probable to have 4 200mbit users active at once on a 800mbit pipe than it is 2 200mbit users on a 400mbit pipe?

[kwikbreaks]

Originally Posted by roughbeast

Now that's a question I always wanted the answer to Chrysalis. I wonder if Ignition has the answer.

Did I do good?

No you didn't. Ignition said he has Chrysalis on his ignore list so doesn't see his posts when logged in. You need to quote or repeat the specific text you want answering and hope a) you get an answer and b) that the answer is correct.

---------- Post added at 08:43 ---------- Previous post was at 08:34 ----------

Originally Posted by Chrysalis

... the only way to reduce the users is either to move some to another segment, or split the node into smaller nodes. If there is a 3rd way someone is welcome to tell me.

They can continue as they are and just let everything go to rats so folks leave. That will eventually balance out as a service that meets the needs of the (remaining) customers.

I suspect that they will be putting their faith in Traffic Management Mk II though as trailed by the man with inside info. If that does indeed sort out the highly overutilised areas it will seriously miff the users causing the problem and they may well end up moving on giving the effect of the old "detrimental use" letters but still allowing the holy grail of VM marketing - "unlimited" to be used in their adverts.

[roughbeast]

Originally Posted by Chrysalis

Well he said they had too many users per segment, so by that I assume he means the node sizes need to be reduced as realistically the only way to reduce the users is either to move some to another segment, or split the node into smaller nodes. If there is a 3rd way someone is welcome to tell me.

So the way I see it if VM are to reduce node sizes in an attempt to support higher speeds then its logical to have those nodes still as one but with the extra capacity instead.

Do you agree its less probable to have 4 200mbit users active at once on a 800mbit pipe than it is 2 200mbit users on a 400mbit pipe?

Yes all of us agree with that I think. 4 people are less likely to be using the system all at once than 2 people, whatever the size of the pipe. Someone is more likely brewing a cup of tea or taking a dump. It makes sense, for statistical reasons, to put more people in bigger pipes than spreading them over a number of smaller pipes.

You feel that Ignitions logic regarding size of nodes is to have smaller ones to increase capacity, which appears to be contradictory to the above logic.

Well I am sure Ignition can square that logic somehow by pointing out some misconception you may have.

Meanwhile, I do not understand why, if on the Coventry trial we had a 10Gb pipe in reserve, more capacity cannot be put in from the centre. Here I reveal the fact that I need to do some reading. I do know that Coventry was chosen for the trials because it had spare slots at street level. Is that the point then? It is the limited capacity at street level that is the problem and that architectural decisions made historically have limited that capacity, though in some locations more than others. You can only do so much by upgrading kit, such as network cards.

A dullard like me would just say, "Lay some more fibre down then!" I guess that is too expensive.

Perhaps someone could point me in the direction of some really good descriptions of how the network works, so I do not continue stumbling into these conversations knowing less than half the theory!

Edit.............................The above was written whilst Kwikbreaks was responding

[kwikbreaks]

I can't make any informed comment on whether or not larger than 400Mbps pipes are economically possible across the network - I suspect not as it's obvious that the low capacity local pipes are what cause issues when high speed connections get used in anything but short bursts so if it was possible without splashing the cash (or in VMs case extending the already astronomical overdraft) it would have been done.

I can comment on ...

Originally Posted by roughbeast

4 people are less likely to be using the system all at once than 2 people, whatever the size of the pipe. Someone is more likely brewing a cup of tea or taking a dump.

I can quite easily fully utilise my connection while doing either of those things. I'd also suggest that those taking the higher speed connections are far more likely to be doing so than 10Mbps customers whose connections quite possibly do consume nothing while they take a leak etc.

[Chrysalis]

Originally Posted by kwikbreaks

I suspect that they will be putting their faith in Traffic Management Mk II though as trailed by the man with inside info. If that does indeed sort out the highly overutilised areas it will seriously miff the users causing the problem and they may well end up moving on giving the effect of the old "detrimental use" letters but still allowing the holy grail of VM marketing - "unlimited" to be used in their adverts.

I agree, I think they banking on that 90% at least as its the cheapest thing to do.

Interesting thoughts on it been used to purposely severely throttle to the point to make the users "want" to leave, it will be interesting to see if VM deliberatly throttle heavily for that purpose. Will we start seeing 0.1mbit speedtests from users who have downloaded a few TB?

---------- Post added at 09:35 ---------- Previous post was at 09:31 ----------

Originally Posted by roughbeast

Meanwhile, I do not understand why, if on the Coventry trial we had a 10Gb pipe in reserve, more capacity cannot be put in from the centre. Here I reveal the fact that I need to do some reading. I do know that Coventry was chosen for the trials because it had spare slots at street level. Is that the point then? It is the limited capacity at street level that is the problem and that architectural decisions made historically have limited that capacity, though in some locations more than others. You can only do so much by upgrading kit, such as network cards.

Edit.............................The above was written whilst Kwikbreaks was responding

I agree with kwikbreaks on this in that the reason it probably hasnt been done is I expect its more expensive than traffic management and possible node splits, as the superhubs for a start are only capable of 8 downstream channels, so new modems would need to be issued for 16. So the truth is most likely cost. So instead of abandoning the idea VM just going ahead anyway and probably hoping the new traffic management does enough and that hardly anyone signs up and uses it. As the primary gain of 200mbit is marketing boasting rights, they probably will still make more profit of lower tier lower usage customers. Also bear in mind with the fluff the config will probably be 220mbit not 200mbit.

[Ignitionnet]

Originally Posted by roughbeast

Yes all of us agree with that I think. 4 people are less likely to be using the system all at once than 2 people, whatever the size of the pipe. Someone is more likely brewing a cup of tea or taking a dump. It makes sense, for statistical reasons, to put more people in bigger pipes than spreading them over a number of smaller pipes.

You feel that Ignitions logic regarding size of nodes is to have smaller ones to increase capacity, which appears to be contradictory to the above logic.

Well I am sure Ignition can square that logic somehow by pointing out some misconception you may have.

Yes, reducing node size doesn't reduce the total bandwidth available it reduces the amount of modems sharing it and increases capacity per modem.

Splitting a 1000 home node (more accurately called a service group) with 400 active customers on it, for the sake of argument all on the DOCSIS 3 network served by 4 downstreams and 2 upstreams, 200Mb down and 2 x 18Mb up into 2 x 500 home nodes both of which will also have 4 downstreams and 2 upstreams doubles available bandwidth per home passed and improves statistical contention as the cohort size is smaller, from 400 to 200 modems.

Yes it still takes only 2 x 100Mb users using their full capacity simultaneously to saturate either node, but if there were say 8 100Mb customers on the 1000 home node and there's only 4 on each of the 500 home nodes the maths looks much healthier.

---------- Post added at 13:59 ---------- Previous post was at 13:55 ----------

Originally Posted by roughbeast

Meanwhile, I do not understand why, if on the Coventry trial we had a 10Gb pipe in reserve, more capacity cannot be put in from the centre. Here I reveal the fact that I need to do some reading. I do know that Coventry was chosen for the trials because it had spare slots at street level.

There was some spare room on the RF network at Coventry for the extra 8 downstreams and 2 upstreams you guys were provided.

The 10Gbps was to ensure that you guys wouldn't run out of core bandwidth.

The issue is, and remains, the DOCSIS downstreams and upstreams that serve the areas, 10Gbps or 1Gbps is irrelevant if there's only 800Mbps hitting the uBR, and having the extra room out of the back of the uBR is pointless for congestion relief if an area's DOCSIS network is overloaded.

The bottleneck is usually that last few hundred metres, not the core network, so anything past that bottleneck doesn't help. You still connect to the uBR at 200Mbps-400Mbps shared between your node / service group however many 10Gbps backhauls come out of the back of it.

[finaldest]

Hi all
New to the forum and have been following this discussion so thought I would register.

A question for Ignitionnet regarding
quote "The bottleneck is usually that last few hundred metres"

If this is indeed the case would it not be in VM best intrest to upgrade the cable run from the cabinet to FTTH? If this is possible in order to remove the bottleneck.

[greeninferno]

why can't Virginmedia specifically target those using torrents and just those users?

[kwikbreaks]

Originally Posted by greeninferno

why can't Virginmedia specifically target those using torrents and just those users?

They say that they do but the number of areas with severe upstream contention says it must be very easy to evade the shaping.

Plus you can screw it all up with nntp which they don't effectively shape or even http downloads from file hosting sites.

Apparently TM Mk2 will be more load and byte count based so all those who CBA to use a PVR will be moaning too then.

[Chrysalis]

Originally Posted by greeninferno

why can't Virginmedia specifically target those using torrents and just those users?

its not a good way to go about it to be honest.

its ok to target heaviest users but I dont agree with targeting protocols.

Also VM have already tried to target torrents and its evident its not an efficient way of traffic management.

1 - light torrent users get penalised which when they are light users isnt really a fair way to deal with it.
2 - there is false positives which seems to mainly affect gamers.
3 - it can be easily evaded which defeats the purpose of it in the first place.

The new system which is due early next year which will not target torrents but will get a lot of torrent users anyway as it will target heavier users. It will not be evadable other than to stop downloading/uploading.

How effective will be remains to be seen, I expect in some areas it will need to be draconian to be effective.

[roughbeast]

Thanks for all the info and analysis guys. I am gradually getting to grips with it.

I found this useful presentation from way back. Hopefully other novices will find it useful too. (You will need to run it in IE though.)

http://homepage.ntlworld.com/draig.goch/

[Andrewcrawford23]

it is a little out of date but mostly right or it works fien in other browsers nto jsut ie

---------- Post added at 09:58 ---------- Previous post was at 09:56 ----------

Originally Posted by Chrysalis

its not a good way to go about it to be honest.

its ok to target heaviest users but I dont agree with targeting protocols.

Also VM have already tried to target torrents and its evident its not an efficient way of traffic management.

1 - light torrent users get penalised which when they are light users isnt really a fair way to deal with it.
2 - there is false positives which seems to mainly affect gamers.
3 - it can be easily evaded which defeats the purpose of it in the first place.

The new system which is due early next year which will not target torrents but will get a lot of torrent users anyway as it will target heavier users. It will not be evadable other than to stop downloading/uploading.

How effective will be remains to be seen, I expect in some areas it will need to be draconian to be effective.

what method are you talkign about coming out next year as all known methods for targetting heavy users to my knowledge can be evaded so just wondering which method you mean so i know if it is one (no i aint aheavy user but i do download more than the limits on stm currently so it could affect me so ill need to know if i should change the way i download like i did for stm)