Why are Minimum Speed Guarantee different between ISPs ?

So if all (or most) ISPs rely on Openreach for a 1000/115 circuit and they all advertise at 900/100 (except AAISP) because of Advertising Standards Agency.

and ASA also wants ISPs to publish averages of Minimum Speed Guarantee etc here is a list

BT - 700
EE - 700
Sky - 600
Vodafone - 455
Zen - 450

Can I assume that either their customer fibre lines to the property are poor, or the ISP infrastrucre is poor, or they don't purchase enough bandwidth ?

Hi,

In reply to a post by einsteinagogo:

So if all (or most) ISPs rely on Openreach for a 1000/115 circuit and they all advertise at 900/100 (except AAISP) because of Advertising Standards Agency.

and ASA also wants ISPs to publish averages of Minimum Speed Guarantee etc here is a list

BT - 700
EE - 700
Sky - 600
Vodafone - 455
Zen - 450

Can I assume that either their customer fibre lines to the property are poor, or the ISP infrastrucre is poor, or they don't purchase enough bandwidth ?

The short answer is that they are all making a guess and crossing their fingers. Openreach guarantee 110Mbits/sec download on a notional 1Gbits/sec FTTP connection so the ISP could find itself stuck between their customer and Openreach at all of those speeds listed. The ISP knows that Openreach generally exceed the minimum speed that Openreach warrant and are therefore taking a punt that they will be OK. The different minima probably reflect a different willingness to take on commercial risk.

but if these are just all random Minimum Speed Guarantee which are advertised, why would anyone sign up with Zen or Vodafone at half, what others are guaranteeing ?

Each ISP will have their own statistics for the average download per customer, and the way that varies with time of day. Different ISPs may attract a different demographic of user - e.g. some may well attract more technical users that want low latency for online gaming, while other attract people that just stream netflix in the evenings, or whatever.
So, each ISP will choose a minimum guaranteed speed that they feel comfortable to offer, allowing for their user demographic and their infrastructure.
There may also be differences in what recourse customer has if the minimum guarantee isn't reached - some ISPs may allow you to break a long contract, while others may only offer a £20 credit up to 4 times a year.

Edited by sheephouse (Mon 25-Mar-24 16:36:30)

Judging by all the backhaul complaints re zen that minimum speed guarantee might be close to reality.

Hi,

In reply to a post by einsteinagogo:

but if these are just all random Minimum Speed Guarantee which are advertised, why would anyone sign up with Zen or Vodafone at half, what others are guaranteeing ?

Because no-one looks at the numbers, because other factors (e.g. price) are often considered more important and because the numbers are meaningless anyway?

yep, maybe it's to keep people away!

In reply to a post by einsteinagogo:

So if all (or most) ISPs rely on Openreach for a 1000/115 circuit and they all advertise at 900/100 (except AAISP) because of Advertising Standards Agency.

and ASA also wants ISPs to publish averages of Minimum Speed Guarantee etc here is a list

BT - 700
EE - 700
Sky - 600
Vodafone - 455
Zen - 450

Can I assume that either their customer fibre lines to the property are poor, or the ISP infrastrucre is poor, or they don't purchase enough bandwidth ?

Why would you assume that?

AAISP have a 195Mb/s Minimum speed guarantee on their 1000/115 package.

https://www.aa.net.uk/broadband/fttp-speeds/

Openreach guarantee 110Mb/s.
If the provider doesn't meet the guarantee they can't do much about it except let you leave your contract penalty free.

Well my assumption is based on if these average speeds published by ISPs based on data from clients and confirmed by speeds for AA

Looks like smaller the ISP slower average speeds is this because they have less infrastructure, because of smaller numbers of clients or they purchased less backhaul connection?

Larger ISPs publishing much higher figures eg 700 from EE/BT

Seems a ripoff if the service being resold is 1000/115 - why do we all not get 900+ all the time or is it like booking seats on a plane if everyone turns up - people get bumped - oversubscribed

Similar with if we all download 900+ , not enough bandwidth at the ISP so contention just farms out 700 each to artificially meet the minimum guarantee to avoid penalties

In reply to a post by einsteinagogo:

Well my assumption is based on if these average speeds published by ISPs based on data from clients and confirmed by speeds for AA

Looks like smaller the ISP slower average speeds is this because they have less infrastructure, because of smaller numbers of clients or they purchased less backhaul connection?

Larger ISPs publishing much higher figures eg 700 from EE/BT

Seems a ripoff if the service being resold is 1000/115 - why do we all not get 900+ all the time or is it like booking seats on a plane if everyone turns up - people get bumped - oversubscribed

Similar with if we all download 900+ , not enough bandwidth at the ISP so contention just farms out 700 each to artificially meet the minimum guarantee to avoid penalties

The GPON delivery to the end user is 2.4GBps shared between the users on the same fibre supplied from wherever the headend is. If you have a 12 port CBT, which is what we have for the GPON service in our road then you get 1/12th of 2.4Gbps, that is 200Mbps, if all the ports are enabled and each customer is simultaneously using their connection as fast as it will go.

The different figures you are seeing are based on what the ISP in question expects in terms of the fibre connection to you and how many users are expected on average, then similar calculations on the next levels of interconnection back to your ISP's own network which will be dimensioned according to what said ISP expects in terms of customer numbers and traffic levels.

Maybe one day there will be enough bandwidth and server capacity for no contention, but it's not here yet. It will be possible to increase the speeds over the fibre but to do so will require the replacement of the ONTs and the headends on the fibres reaching the customer premises.

Interesting that’s going to cause issues with BT/EE and there 700 min guarantee

So that begs a question is there are priority as to who gets what bandwidth at the pole?

If you connected at 1000/115 compared to 150/30

If it’s contended at the pole

Why pay for 1000/115 if you cannot use it all the time because it’s shared out of 2.4

In reply to a post by einsteinagogo:

Interesting that’s going to cause issues with BT/EE and there 700 min guarantee

It isn't. The likelihood of that being congested is very low. If you do get less and complain you will be free to leave.

So that begs a question is there are priority as to who gets what bandwidth at the pole?

Nope.

Why pay for 1000/115 if you cannot use it all the time because it’s shared out of 2.4

Residential broadband (and most business broadband) is a shared/contended service. As is the vast majority of the wider internet.

If you want a guaranteed 1000Mb then you are going to need to pay hundreds a month for a dedicated leased line.
That would only guarantee those speeds between you and your provider. The internet beyond your ISP comes with no such guarantees no matter how much money you want to throw at it.

People use the internet in bursts. Most people don't take the highest speed packages.
Bottlenecks on the Gpon section of the connection are extremely rare.
People wouldn't want to pay what it would cost to build the network in such a way that there's sufficient capacity/bandwidth for everyone to max out their connections at the same time.
It would be a silly waste of money to do so.

A provider can choose to offer as low or as high a guarantee as they want. It says nothing about the condition of their network.
They only need to demonstrate they can provide the headline rate (900Mb for example) on average at peak times.

Openreach provides different minimum rates for different contractual levels.

The rate you sign up for is known as the PIR (Permitted Information Rate); the guaranteed rate is the CIR (Committed Information Rate). So, for example, the BT 900/110 product maps on to the Openreach 1000/115 product, which has a PIR of 1 Gbps and a CIR of 110 Mbps. The OR 120/20 product has a PIR of 120 Mbps and a CIR of 55 Mbps.

Note that the CIR doesn't change with every PIR - most OR products above 160 Mbps PIR have a CIR of 110 Mbps.

However, with FTTP you are never "connected at 1000/115 compared to 150/30" as you put it. The connection between your ONT and the ISPs OLT is always 2.48 Gbps downstream and 1.2 Gbps upstream. The throughput limitation happens inside the network switches using a technique called traffic policing.

A bit of a simplification, but the process works roughly as follows:
- each of the your packets has a tag associated with it which indicates whether it can be discarded by a switch
- if you start to exceed your CIR (your guaranteed rate) your packets get tagged as "eligible for discard"
- if there is still spare capacity on your PON (no-one else needs it at that point), then they won't be dropped, and you'll get throughput above your CIR
- if capacity is starting to be limited (others are also busy) then some of your packets are likely to be dropped - if others are also exceeding their CIR, then their packets will also be dropped, and everyone will see reduced throughput
- if you were to start to exceed your PIR (what you've paid for) then your packets will be dropped

Very helpful

Is there a technical Openreach document which explains the technical details of Broadband in the UK?

Openreach publish their Suppliers Information Notes (SINs) here: https://www.openreach.co.uk/cpportal/help/suppliers-...

Other networks use faster fibre options, XG-PON, and XGSPON for example. Openreach so far have not (apparently) deployed this. Non-openreach networks include wholesale CityFibre (and apparently nexfibre) as well as ISP-specific operators such as Toob, and Zzooom.

In reply to a post by einsteinagogo:

Why pay for 1000/115 if you cannot use it all the time because it’s shared out of 2.4

Because 99.9% of the time you can, and in the other 0.1% you won't notice anyway.

There are a mixture of people on your street sharing the PON, from hardcore gamers to OAPs who do nothing more than download E-mails.

Even the hardcore gamers aren't downloading games all the time - they have to spend time playing those games too.

Beyond a certain point, giving people higher download speeds doesn't increase the amount of data they download. They just do it in a shorter time, which means you are less likely to be using the network at the same time as them. That's why EE aren't worried about selling 1.2G and 1.6G services on a shared 2.4G GPON.

*Average* usage of a home Internet user is about 500GB per month(*), which if you spread it out is only 1.6Mbps. Obviously it goes up and down over a 24 hour period, but even in the "peak hour" it's only likely to be 5-10Mbps.

(*) OFCOM 2023 report, figure for 2022 I think.

In reply to a post by potterer:

Openreach provides different minimum rates for different contractual levels.

The rate you sign up for is known as the PIR (Permitted Information Rate); the guaranteed rate is the CIR (Committed Information Rate). So, for example, the BT 900/110 product maps on to the Openreach 1000/115 product, which has a PIR of 1 Gbps and a CIR of 110 Mbps. The OR 120/20 product has a PIR of 120 Mbps and a CIR of 55 Mbps.

PIR is Peak Information Rate not permitted.
There is another value used in the industry which is EIR - Excess Information Rate, which is essentially PIR-CIR.

CIR that Openreach quote in their product spec and SINs is NOT actually a CIR. CIR should be a guaranteed rate, however in Openreach's case it is a statistical marketing value that they hope you will be able to achieve most of the time.

On PON networks when you configure a CIR that value is reserved bandwidth on the PON which you are guaranteed to get. Openreach use 1:32 split, so if you assume they use a max of 30 ports they could have 3.3G of CIR, they only have 2.48G as they use GPON, so it cannot be configured as a CIR on their network.

Prioritisation on PON is done via T-CONs and GEMs but works much as potterer says for switches.

Hi,

In reply to a post by Ad_G:

In reply to a post by potterer:

Openreach provides different minimum rates for different contractual levels.

The rate you sign up for is known as the PIR (Permitted Information Rate); the guaranteed rate is the CIR (Committed Information Rate). So, for example, the BT 900/110 product maps on to the Openreach 1000/115 product, which has a PIR of 1 Gbps and a CIR of 110 Mbps. The OR 120/20 product has a PIR of 120 Mbps and a CIR of 55 Mbps.

PIR is Peak Information Rate not permitted.
There is another value used in the industry which is EIR - Excess Information Rate, which is essentially PIR-CIR.

CIR that Openreach quote in their product spec and SINs is NOT actually a CIR. CIR should be a guaranteed rate, however in Openreach's case it is a statistical marketing value that they hope you will be able to achieve most of the time.

On PON networks when you configure a CIR that value is reserved bandwidth on the PON which you are guaranteed to get. Openreach use 1:32 split, so if you assume they use a max of 30 ports they could have 3.3G of CIR, they only have 2.48G as they use GPON, so it cannot be configured as a CIR on their network.

Prioritisation on PON is done via T-CONs and GEMs but works much as potterer says for switches.

Note that you are assuming that it is actually a 1:32 split and that everyone on the PON has ordered a >=160M service.

The reality is that
a) most PONs will not be fully occupied (and Openreach only design to a maximum of 1:30 split, the extra 2 are for contingency)
b) most people ordering FTTP will not order the higher tiers so they probably can commit to the "Prioritised Downstream" rate even if the whole PON is occupied.

I understand that Openreach will consider splitting PONs where they can't guarantee the "Prioritised Downstream" rate.

Those on XGS-PON shouldn't feel smug:
- they may have a higher headline data rate but
- the split could well be 1:128 which gives a slightly worse full rate split than 1:32 on PON but
- they do benefit from better statistical spreading of traffic but
- that is offset to some extent by offering high headline rates (e.g. > 1G) which could allow a few users to use large amounts of bandwidth and saturate the PON.