Why you don't get the whole 100mbps in UFB and Why it's capped to 100mbps only??

Forums › New Zealand Broadband › Why you don't get the whole 100mbps in UFB and Why it's capped to 100mbps only??

DizzyRevo

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#119584 6-Jun-2013 17:09

Hello
When I saw UFB users speed tests I saw most of them get between 86 to 90+ but no one gets the full hundred and Why it's only a hundred Places Like Canada has 250 mbps or US or Europe has very high speeds even UAE has 300 mbps plan but to be honest most of plans their are 100 mbps
is it the initial speed only, then more speeds will be allowed or what?
thanks a lot

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Vocus

#831728 6-Jun-2013 17:13

100Mbps is the line speed, once you take overheads into account (packet headers, encapsulation, etc) then you get 80-90Mpbs (which is what, eg, Speedtest will report).

The technology (GPON) is capable of gigabit speeds. I can't see any reason there won't be higher speed plans made available down the track, but for now I guess 100Mbps serves the market adequately. Someone from Chorus or one of the other LFCs might have a better answer on this one.

muppet

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#831729 6-Jun-2013 17:14

Many different reasons.

Where are you measuring your "100" to? You have to remember the server you're measuring too might have a lot of bandwidth, or it might have some problems itself. Just because your street is 200 meteres wide and has no traffic in it in the morning when you leave home, doesn't mean you will get a hassle-free drive into the car park at your work. You get close to work there's other traffic!

Here's something I wrote a while ago that might help you in your understanding a bit more.

http://www.geekzone.co.nz/muppet/7448

mercutio

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#831743 6-Jun-2013 17:32

from what i've seen it's worse on chorus. basically, speed is provisioned as maximum speed, and as soon as you send too much traffic it's dropped, so any minor delays or jitter in sending can reduce speed.

generally speaking 100 megabit is normally provisioned on gigabit with a small amount of burst to actually give 100 megabit throughput, but if deploying on 100 megabit or having some anal rate policer then your experience is going to degrade.

unfortunately the government has created a monopoly reducing competition and differentiation.

in the US normal cable plans come with significant burst, as well as higher speeds but that cannot be offered in NZ unless ISP does something like give 50 megabit burst to 100 megabit for 15 seconds.

the same applies for gigabit and 10 gigabit btw. so he.net are selling "cheap" gigabit services that you can't really get gigabit on as it's max line rate, rather than a faster provisioned line. i think cost is around $700 USD with $200 cross connect or thereabouts. but if you want real gigabit over 10 gigabit they bump up the cost.

i'd expect you'd find similar issues on gigabit connection if they did it.

normally a 100 megabit connection can do ~94.5 megabit/sec with tcp/ip btw. so you should expect to see speeds more like that. with jumbo frames and gigabit can do ~970 megabit/sec.

anyway dsl is similar. if you have 25000 sync rate you should be able to get (~94.5/4) or aproximately 23.6 megabit.. but you're more likely to get around 21 megabit.

raytaylor

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#832690 8-Jun-2013 15:17

ubergeeknz: 100Mbps is the line speed, once you take overheads into account (packet headers, encapsulation, etc) then you get 80-90Mpbs (which is what, eg, Speedtest will report).

The technology (GPON) is capable of gigabit speeds. I can't see any reason there won't be higher speed plans made available down the track, but for now I guess 100Mbps serves the market adequately. Someone from Chorus or one of the other LFCs might have a better answer on this one.

I am pretty sure gigabit is avaliable to the ISP's but its very expensive.
I have been told that the PON head ends are capable of 2.5gbits.

So

You get connected to a GPON headend with a 2.5gbit downstream capability.
That is divided up by 32 or 64 end users, each with a 30 or 100mbit connection. This is actually the Peak Information Rate or PIR

Your CIR or Committed information rate is actually about 2.5mbit.

So if there are 64 users attached to the PON head end, they will each get 2.5mbit or whatever dedicated capacity the ISP buys for them.
Thats 160mbit of the 2.5gbit reserved for dedicated purposes. The remainder of the 2.5gbit gets divided up by whoever wants to use it at the time, with no one user exceeding their PIR

If 64 users all started downloading (and the ISP's were able to feed the head end at full capacity) then each user on a 100mbit plan would be able to get 39mbps.

If you want to have a full 100mbit dedicated - the ISP needs to buy a dedicated point to point connection, or buy a PON connection with a higher CIR

Because GPON is a shared connection technology, it is priced cheaper alternative than running point to point fibre links everywhere. To get the dedicated connections they are usually sold as either a business dedicated connection, or the ISP can get the price down by using a UFB Gpon connection but buy a higher CIR for the connection to get the same effect.

The reason gigabit is not currently in the cheaper price bracket (in my opinion) is that if the head end is capable of 2.5gbit, suddenly having two gigabit tails connected to it will use a considerable amount of bandwidth and it no longer becomes practical to have 32 or 64 connections attached to it - which is how fibre has become so cheap under UFB.
In the future, head ends with higher capacity can be used (like replacing an ADSL dslam with an ADSL2+ one) and faster plans can be offered, without having to upgrade existing equipment at the receiver end. One way I see to increase capacity would be to add another light frequency and they could double the head end capacity.

Ray Taylor

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sbiddle

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#832694 8-Jun-2013 15:37

ubergeeknz:
The technology (GPON) is capable of gigabit speeds. I can't see any reason there won't be higher speed plans made available down the track, but for now I guess 100Mbps serves the market adequately. Someone from Chorus or one of the other LFCs might have a better answer on this one.

GPON techn ology supports 2.4Gbps down and 1.2Gbps up which is split between all users on the GPON node. To avoid over contention Chorus and all the LFCs in NZ will only provide 100Mbps services over GPON as they're splitting the connection to 24 subscribers.

Both 1Gpbs and 10Gbps are part of the UFB wholesale pricing and are available from Chorus or any of the LFCs. These are P2P conections however, not GPON.

With the 10G-PON standard now finalised there is some gear hitting the market. As both GPON and 10G-PON can co-exist on the same fibre in future Chorus or any of the LFC's could upgrade to this by pretty much adding a new OLT and upgrading the ONT's as required.

sbiddle

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#832695 8-Jun-2013 15:42

mercutio: from what i've seen it's worse on chorus. basically, speed is provisioned as maximum speed, and as soon as you send too much traffic it's dropped, so any minor delays or jitter in sending can reduce speed.

EIR is queued when you exceed it, CIR discards packets when you exceed it. This is how the CIR works on current HSNS and fibre deployments which are in effect only a CIR connection.

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DarthKermit

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#832908 9-Jun-2013 09:39

Why did I never get the full 56k connection from my dialup modem, back in the dark ages? I shoulda gone to Fair Go.

Whatifthespacekeyhadneverbeeninvented?

mercutio

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#832938 9-Jun-2013 10:43

DarthKermit: Why did I never get the full 56k connection from my dialup modem, back in the dark ages? I shoulda gone to Fair Go.

weird i got more than 56k out of my 56k modem :)

generally speaking with 28.8k modems you could always get full speed syn, but 33.6k could often only get up to 31.2k sync.

modems had inbuilt compression, meaning that commonly web pages could go 8k/sec etc. especially when you disabled images because you didn't want to wait an age for pages to load.

generally speaking, i found 128kbit jetstart similar to dialup in speeds for single user, but it shared slightly better.

wired

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#832944 9-Jun-2013 11:06

sbiddle:EIR is queued when you exceed it, CIR discards packets when you exceed it.

From what I have seen, both are discarded when you exceed the rate and the burst buffer is full.

wired

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#832953 9-Jun-2013 11:26

With the same number of people on a PON fibre with faster plans there is more chance of two people downloading at the same time and therefore congesting the network even if it is only briefly. When congestion occurs, there is a chance that packets will be dropped because the queues are not big enough to handle the congestion.

The government has specified 100 Mbps plans with a maximum of 2% packet drop. With only 2.5 Gbps available in the DS, the PIR of the plans needs to be such that enough people can use the same shared fibre to get the $ benefits of PON while avoiding congestion and therefore packet drop. If the 2% packet drop limit was got rid of, then the LFCs could allow more congestion in their networks and hence probably offer faster plans.

mercutio

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#832956 9-Jun-2013 11:29

wired: With the same number of people on a PON fibre with faster plans there is more chance of two people downloading at the same time and therefore congesting the network even if it is only briefly. When congestion occurs, there is a chance that packets will be dropped because the queues are not big enough to handle the congestion.

The government has specified 100 Mbps plans with a maximum of 2% packet drop. With only 2.5 Gbps available in the DS, the PIR of the plans needs to be such that enough people can use the same shared fibre to get the $ benefits of PON while avoiding congestion and therefore packet drop. If the 2% packet drop limit was got rid of, then the LFCs could allow more congestion in their networks and hence probably offer faster plans.

you're not going to get 100 megabit transfer speeds with 2% packet loss though. i'd rather some kind of round robin scheduling between the ports myself, and to just have gigabit.

2.5 gigabit to 24 users is heaps, but i expect there'll only be gigabit backhaul generally to keep costs down.

i'm not quite sure how there's more chance of two people downloading at the same time though. given the same usage limits and faster connections there should be less chance of two people downloading at the same time because things download quicker.

anyway, for the most part it's a con. the vast majority of users won't want to pay for expensive internet, and it'll mean that copper is deprioritised for the majority of customers staying on copper be it for cost reasons, renting, or lack of availability.

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raytaylor

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#833188 9-Jun-2013 19:32

mercutio:

you're not going to get 100 megabit transfer speeds with 2% packet loss though. i'd rather some kind of round robin scheduling between the ports myself, and to just have gigabit.

To be honest, if someone is moaning about only getting 95mb on a 100mbit connection - they are probably the same people that complain about their 160gb hard drive only having 148gb of usable storage capacity.

You mention something interesting - round robin.
To avoid collision collapse, the upstream uses TDMA timing in a round robin fashion so the ONT's on each tail connection will take turns to upload data back to the PON head end.

Ray Taylor

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mercutio

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#833192 9-Jun-2013 19:41

raytaylor:
mercutio:

you're not going to get 100 megabit transfer speeds with 2% packet loss though. i'd rather some kind of round robin scheduling between the ports myself, and to just have gigabit.

To be honest, if someone is moaning about only getting 95mb on a 100mbit connection - they are probably the same people that complain about their 160gb hard drive only having 148gb of usable storage capacity.

You mention something interesting - round robin.
To avoid collision collapse, the upstream uses TDMA timing in a round robin fashion so the ONT's on each tail connection will take turns to upload data back to the PON head end.

i'm more concerned about 90 megabit on gigabit.

Lazarui

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#833211 9-Jun-2013 20:22

DizzyRevo: Hello
When I saw UFB users speed tests I saw most of them get between 86 to 90+ but no one gets the full hundred and Why it's only a hundred Places Like Canada has 250 mbps or US or Europe has very high speeds even UAE has 300 mbps plan but to be honest most of plans their are 100 mbps
is it the initial speed only, then more speeds will be allowed or what?
thanks a lot

Hmmm, I Have a but if an eyebrow raise when-ever I hear the X/Y country gets X/Y speeds... When you look at US, or europe getting X speeds.

It's not a national coverage plan, It's generally in isolated area's. What most people don't realise is the majority of the united states is still on xDSL technologies the same with Europe I can't speak for the UAE, but I remember a few years ago they were listed in the bottom quartile as far as quality of high speed internet. (There are some exceptions like south korea, Which I know has a insane Fibre penetration).

Also you need to take into account Things like UFB have little bearing until we get better about local content and caching, xDSL technologies are more than adequate for most current uses (If customers have the correct equipment, and a splitter installed) IF we were heavier on local content, alot of what I hear from people with thier "Speed problems" is some obscure site or service hosted in the america's somewhere.

Don't get me wrong I'm happy we're being pro-active in this case, but it almost feels like putting the cart before the horse, maybe the goverment should be throwing some incentive out there for bigger Data farms being built We're going to have this great internal network that has alot of oppurtunity but it will be severly under utilised until services here are competitive.

mercutio

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#833419 10-Jun-2013 10:25

Lazarui:
DizzyRevo: Hello
When I saw UFB users speed tests I saw most of them get between 86 to 90+ but no one gets the full hundred and Why it's only a hundred Places Like Canada has 250 mbps or US or Europe has very high speeds even UAE has 300 mbps plan but to be honest most of plans their are 100 mbps
is it the initial speed only, then more speeds will be allowed or what?
thanks a lot

Also you need to take into account Things like UFB have little bearing until we get better about local content and caching, xDSL technologies are more than adequate for most current uses (If customers have the correct equipment, and a splitter installed) IF we were heavier on local content, alot of what I hear from people with thier "Speed problems" is some obscure site or service hosted in the america's somewhere.

I think this is highly relevant in some ways.

For me on DSL, most sites load pretty fast, and there's three things that seem to slow them down:

* Slow dynamic page generation on the host (most pages are dynamic)
* Distant locations, or inadequete low performing caches being used (like akamai which somehow seems to always be terrible for non-cached content, and often seems to have non-cached content)
* Flash/Advertisements/Facebook/bling - these things always seem to slow pages down

That said, it'd be nice if google and facebook had nz nodes/locations for caching, services etc. but not many google services even seem to be in australia atm, so chances are reasonably low.

Facebook seems to use akamai edgecast now days for images which seems to put it into the "don't cache in NZ category". On top of that akamai are slower than CDN's that use higher window sizes, ssd caching etc and often seems to have terrible cache miss performance (probably due to bad tcp/ip settings there too, but maybe hard-disk overload etc too)

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