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Broadband network capacity update - Discussion

Liam
Grafter
Posts: 2,083
Registered: 04-04-2007

Broadband network capacity update - Discussion

Following on from Neil's announcement here, please use this thread for discussion.

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Introduction
Our biggest challenge over the last two years has been balancing the need to have a profitable and scalable product proposition whilst delivering good value to our customers. While we’ve been doing this, the use of broadband applications has exploded, yet the wholesale infrastructure that all ISPs work with has not scaled accordingly. In 2006 we saw increasing average usage, driven by faster speeds and more video and music downloads. We envisage that this growth in usage will continue throughout 2007, due to new technologies like Web 2.0 and TV on demand.

When we design any broadband product we plan to provide an amount of network capacity per customer. That drives how much capacity we buy, which in turn drives our costs. To allow for the envisaged growth in usage, we intend to increase the amount of network capacity per customer. We believe that this extra scale will provide an excellent customer experience.

New BT Central pipe on order
We have now ordered an additional 622Mb/s BT Central pipe, which we expect to be available in March. We intend to activate two segments of this immediately; this means our total capacity will grow by 12.5%. Our estimated timescales are based on the lead times being met by both BT and our network equipment suppliers.

A key issue we face at the moment which is affecting customers using USB modems on Sunday, Monday and Tuesday evenings is a shortage of sessions. This has been caused by an increase in session concurrency due to an increase in background traffic (caused by viruses) and an increase in the proportion of customers using routers. Adding additional capacity now will provide us with extra sessions at peak times and gives us further room for growth.

We’re taking some short term steps to deal with this including introducing a network-based personal firewall for customers. The PlusNet Usergroup has been giving us some feedback on this.

We are also looking at some alternative network options to give us some short-term increases in sessions ahead of our new BT Central pipe arriving. We will be inviting a group of customers to trial this alternate access network provided by BT in the next week or so. We will trial this with staff accounts first, then PUG members and then open the trial up to the wider customer base. It is likely that this will be open only to Pay As You Go customers and will not support static IP addressing.

2007 & 2008
May 2007 should see new BT Wholesale pricing which will give us the opportunity to review our product designs. We are planning our network strategy with BT which means we will be able to assure the quality and customer experience of our products.

We will be providing more information to all customers by email and on our website when the proposed acquisition by BT completes during the coming weeks.

Kind regards,

Neil Armstrong
Products Director
PlusNet
80 REPLIES
Community Veteran
Posts: 3,364
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Registered: 06-04-2007

Broadband network capacity update - Discussion

Start of .. or end of March, like to choose a week beginning date for March?

SW.
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3Mb FTTC
https://portal.plus.net/my.html?action=data_transfer_speed
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Broadband network capacity update - Discussion

End of March 2008? :lol:
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Broadband network capacity update - Discussion

I don't have a set date I can give at the current moment in time I'm afraid.

Once we near the date we'll be able to give more specific information.
Plusnet Staff
Plusnet Staff
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Registered: 04-04-2007

Broadband network capacity update - Discussion

Adding a central pipe isn't always an easy task, it has to go through thorough planning, it may need new fibre laying, underground tunnels dug, all kinds of things as such it can only be given an estimated date until each stage of planning and installing is complete. As soon as we know, we'll make sure you know.
Community Veteran
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Broadband network capacity update - Discussion

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End of March 2008? :lol:
Is it a new moderator requirement to be so totally cynical so quickly Smiley
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Broadband network capacity update - Discussion

Would you believe me if I claimed it was a typo?

Thought not, ah well.Cool


Back to the point though, I thought that the 622Mbps pipes had a higher number of sessions possible per Mbps than the old-school 155Mbps pipes?

Does running out of available sessions kinda indicate that there are more users than the available capacity suggests there should be?

And if so, doesn't the fact that PN are using 622Mbps pipes rather than 155's also mean that in days gone by there would have had to have been more capacity per user available?

Apologies for not phrasing my thoughts/questions particularly well, but hopefully somebody can pick up on my train of though and expand?


Equally if I have the wrong end of the stick (or even the wrong stick) somebody could point me in the right direction.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Broadband network capacity update - Discussion

My understanding is that using 155's over 622's is less effecient bandwidth-wise.

You can get 32,000 sessions over a 622mbps pipe.
Community Veteran
Posts: 38,216
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Registered: 15-06-2007

Broadband network capacity update - Discussion

Actually the probable reason is that although the total number of sessions on all pipes is OK for the number of users the relatively low user numbers on the Tiscali pipe(16,000 I think) will have skewed the results and overloaded the other pipes.
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Broadband network capacity update - Discussion

I understand the increased efficiency of the 622's, rather I'm a little confused by the capacity/sessions issue.

If you had the same capacity as you have now, but provisioned over 155's instead of 622's, you would have an even larger shortage of free sessions.

Wouldn't it be the case that even if you increased the number of 155's to take into account the inefficiency of them in comparison to the 622's you would still have less sessions than you do now?
Plusnet Staff
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Registered: 04-04-2007

Broadband network capacity update - Discussion

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Back to the point though, I thought that the 622Mbps pipes had a higher number of sessions possible per Mbps than the old-school 155Mbps pipes?


A old-school 155Mbps has 8,000 sessions, but because of the ATM overhead you actually need five 155Mbps pipes to carry the same amount of bandwidth as a single 622Mbps pipe (which has 32,000 sessions).

So on a Mbps per session basis a 622 gives

622 * 1024 / 32,000 = 19.9kbps

while 5 x 155Mbps pipes gives

765 * 1024 / 40,000 = 19.6kbps

with a 622Mbps pipe being 23% more efficient than a 155 that second figure actually drops to 15.1kbps.

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Does running out of available sessions kinda indicate that there are more users than the available capacity suggests there should be?


No, when you look at graphs like this:

http://www.plus.net/support/network_performance/broadband_bandwidth_usage.shtml

there are a large number of people connected whose connections are idle, bear in mind that this graph is a little skewed because it will see people being active but the only traffic on their connection is background noise and random pings, probes and virus scans.
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Broadband network capacity update - Discussion

erm sounds great but whose going to pay for it? If PN expands the number of customers to pay for the new pipe, wont we be back to square one...........................

Seems to me this ISP business can be compared with the problems with roads, congestion, and number of vehicles.
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Broadband network capacity update - Discussion

Thanks for the explanation Dave!

That's the calculations I was thinking of - and I'm pleased to see that my cynicism was unfounded.

Looks all round like good news, so long as the new capacity is based on the numbers of users now, and increases in line with any increase in subscriber numbers.

I read on Kitz's site that you can light up the remaining two segments at any time in the first year.
Does this mean that the additional segments have to be lit by the end of 12mths, or can they remain unlit indefinitely?

Also (I know you might not know the answer, or be able to disclose it if you do) are there specific criteria set by PN which when met will mean the other segments are lit, or is a case of seeing how things go and making a decision when the need arises?
Plusnet Staff
Plusnet Staff
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Broadband network capacity update - Discussion

Quote
erm sounds great but whose going to pay for it? If PN expands the number of customers to pay for the new pipe, wont we be back to square one...........................


First thing to remember is that the BT Wholesale pricing changes in May which as Neil says gives us chance to review our product designs, so it may mean that decreased costs means we can change the amount of bandwidth per customer for example.

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Seems to me this ISP business can be compared with the problems with roads, congestion, and number of vehicles.


Definately, I'm sure I wrote an analogy once comparing traffic management to roads. Might see if I can dig it out (or re-write and update it).
Neil_A
Grafter
Posts: 450
Registered: 04-04-2007

Broadband network capacity update - Discussion

One thing we forgot to put in the post is that we actually ordered the additional pipe at the beginning of November as we always keep a pipe on order so that we can grow at short notice.

We asked BT on 5th January to expidite delivery of the pipe for the reasons outlined in the post, i.e. sessions and room to grow in 2007 as people use more video.