Is your premises phone wiring impacting your broadband performance?

By Steve Biddle, in , posted: 2-Mar-2013 20:50

The vast majority of broadband users in New Zealand receive their broadband connection via copper cable owned by Chorus using ADSL, ADSL2+ or VDSL2 technology.  By far the most common technology in use is ADSL2+ which delivers speeds of up to approximately 20Mbps downstream and 1Mbps upstream. Uptake of VDSL2 is growing and this technology is currently capable of delivering speeds of up to 70Mbps downstream and 10Mbps upstream, averaging around 40Mbps down and 10Mbps up. Between 2008 and 2011 over $1 billion was spent by Telecom rolling out a Fibre To The Node (FTTN) network which consisted of over 3500 new roadside cabinets across the country, all connected by fibre optic cable. Because the speeds of all copper based technologies are limited by distance, bringing fibre fed cabinets with equipment to deliver internet closer to people’s homes meant approximately 85% of premises in New Zealand are capable of receiving an internet connection of at least 10Mbps using ADSL2+, and around 40% capable of receiving VDSL2.

(For the rest of this post I will use the term xDSL to refer to DSL technology as a whole, this includes ADSL, ADSL2+, VDSL, VDSL2 and SHDSL)

What is clear however is that the actual number of people who are receiving a 10Mbps connection is significantly below this figure. The reason for this happening is also pretty clear – apart from distance, xDSL performance is dependant on the quality of the copper cable that’s delivering the services. Statistically speaking poor quality phone wiring within the home or office is the single biggest contributing cause when it comes to poor internet speeds or performance. It’s also very clear that the vast majority of people are totally unaware that their home or office wiring is impacting their internet performance.

Before I start to explain how wiring affects your speed it’s important you understand some basics of how how xDSL broadband works.

In the old days the copper cable to your home (known technically as a MPF – Metallic Path Facility) only delivered phone services and used the frequency range from 300Hz up to 4kHz to deliver voice. In the 80’s ADSL was born, allowing both a phone and data connection to share the same copper line by using a frequency range above that used by voice for the data transmission.. ADSL, ADSL2+ and VDSL2 standards all allow broadband to co-exist with voice. The following image (courtesy of Wikipedia) displays a standard ADSL band plan.

File:ADSL frequency plan.svg

As you can see regular ADSL uses the section of spectrum from 25kHz up to 1.1MHz. Newer xDSL standards use even higher frequency ranges to increase speeds, ADSL2+ improves upon ADSL by using up to 2.2MHz, and VDSL2 goes even higher with profiles using up to 8Mhz, 12Mhz, 17Mhz and  30MHz. The 30MHz profile is able to deliver a data rate of up to 200Mbps over several hundred metres.

xDSL divides the available spectrum up into small sections known as carriers, tones or bins (all three mean the same thing and are simply different terminology). ADSL, ADSL2+ and VDSL2 (8MHz, 12MHz and 17MHz profiles) use a carrier width of 4.3125 KHz. Standard ADSL divides the available spectrum into 256 carriers, and ADSL2+ offers greater speeds by using 512 carriers as it doubles the available spectrum. VDSL2 uses anywhere from 2048 up to 4096 carriers depending on the profile type. As the frequency range increases however, limitations of copper cabling start to take effect. While standard ADSL can easily work over 4km or greater, VDSL2 using a 30a profile will only work up to around 300m as the higher frequency ranges are unable to travel as far over copper cable. In many ways this mirrors the radio world where an AM radio station transmitting on 1000kHz will travel a lot further than a FM station transmitting on 100MHz.

While both a phone call and your xDSL can be carried over the copper cable to your premises, to enable the simultaneous use of xDSL and phone at the same time a low pass filter is required to be used to split the signals so that they don’t interfere with each other. This low pass filter is commonly referred to as a line filter or splitter and is pictured below.

plug in dsl filter

Most people will have a  plug in filter on every device in their home that uses the phone line. Without a filter you will be able to hear the xDSL tones if you lift up the phone handset (assuming you’re not tone deaf!), and will typically see xDSL disconnections or high xDSL error rates if you try and use the phone while your modem is connected without filters.

So you’ve got your filters all plugged in and your internet is connected. You probably think everything is sweet.


While a plug in filter splits the voice and xDSL signals, it doesn’t do anything to eliminate other issues that exist in your home wiring that will have an impact on your xDSL connection. If you have a home alarm it will typically be configured as a “line grabber”, which means your incoming phone wiring will run through the alarm before it connects to the phone jacks in your home. This configuration allows the alarm to isolate the line with a relay before it dials out to a security company, meaning that even if you leave a phone off the hook in your home your alarm will still work. Because of this your xDSL connection will drop every time your alarm dials out. Many medical alarms are also wired in a similar fashion, once again to ensure that a phone off the hook doesn’t prevent the alarm from being able to call out. Alarms can also increase line attenuation and line resistance, which is the next thing you’ll learn about.

So.. Attenuation. What is it?

Copper cable has characteristics which are well known, one of these is attenuation. Simply speaking, the longer a piece of cable, the greater the signal loss will be – a figure known as attenuation. Attenuation is one of the reasons why the speed of xDSL technology decreases the further you are away from a roadside cabinet or exchange. A lower figure is better, so if you’re located right next to a roadside cabinet or exchange your line attenuation may be around 2 – 3dBm, if you’re located 2km away your line attenuation will typically be around 25dB – 30dB.

To confuse matter more, your distance from a roadside cabinet or exchange isn’t the only thing that can cause high attenuation figures. Joints in a cable can also increase attenuation, with the extent of this increase depending entirely on how well the cable is joined. The typical New Zealand home has it’s phone wiring connected in series, this means that your jack  points are all looped together, as the image below demonstrates.


no master filter


Phone wiring in series was recommended practice until the late 90’s when xDSL services started to make an appearance. Telecom started advising in 1998 that phone wiring in series should be avoided, and the current TCF home premises wiring regulations also advise against this. It is still common practice however for many incompetent electricians and data installers around the country to follow this method, and there are still new homes being built where home owners will suffer from a degraded broadband experience, purely because installers can’t be bothered in following industry guidelines that have now been in place for over 14 years. All premises wiring should consist of a structured solution where all jack points connect back to a single location. The TCF website  contains plenty of information regarding this.

So what’s wrong with series wiring?

Each jack point can increase the attenuation on your line by a small amount, and also introduces multiple locations where corrosion can occur, something that’s exceptionally common in damp New Zealand homes. Corrosion in a jack point can cause significant degradation of xDSL. Another common issue is the mixing of newer 2 wire and older master and secondary BT jack points. Until the mid 90’s many older style phones in New Zealand required a master jack point with capacitor to generate a ringing signal carried on a 3rd wire within the premises. The master jack point was fitted where the phone cable entered the premises, and secondary jack points were fitted elsewhere on the premises. These were signified with a M or S in the lower corner of the jack point face plate. These jack points were replaced in the mid 90’s with a single style known as a 2 wire jack  point (as only 2 wires are required to be used within the premises). Mixing older M or S jack points and 2 wire jack points will impact xDSL performance.

Last, but not least, an issue known as a bridged tap (also referred to as a line stub by some people) is a major issue in the xDSL world. A bridged tap is created when wiring is split and occurs if you have multiple jack points installed., regardless if they’re in use or not. If you’ve got 5 jack points on your premises for example any xDSL signals travelling along the copper cable to your home are transmitted not just to the jack point that has your modem connected, but to the other 4 as well. These signals then reflect back from these other jack points and cause  interference to the xDSL signal, ultimately degrading the performance of your broadband connection. Higher frequencies are affected to a far greater degree by a bridged tap, so they’re not so noticeable if you’re using ADSL but can have a large impact on ADSL2+ and VDSL2. Bridged taps can also exist in Chorus wiring external to your home where wiring may be looped down your street, but the instances of this are now very low.

So now that I’ve told you everything that’s wrong with your connection, I’ll tell you how to fix it. The solution is simple – it’s called a master filter.


A master filter does exactly the same job as a plug in filter – it’s a low pass filter that splits voice and xDSL signals. What it does differently is eliminating all of the internal wiring issues discussed above, essentially isolating your xDSL from your home wiring. A master filter is installed at the point where your phone cabling enters your premises, with the xDSL output of the master filter connected to a dedicated xDSL only jack point somewhere on your premises. The voice output of the master filter is then connected to your existing phone wiring. You’ll still be able to use your phones anywhere on the premises, but will only be able to plug in your xDSL modem to the dedicated xDSL jack point.

master filter

Because the master filter isolates the premises wiring issues from the xDSL signal it means all of the issues I’ve discussed above can no longer impact your broadband performance.

It’s a common myth that having a naked xDSL connection (a xDSL connection without a phone) removes the need to use any filters. This is incorrect. While plug in filters are not needed as there is no need to split voice and xDSL signals, a naked xDSL service will still continue to be impacted by premises wiring issues that can only be eliminated by the installation of a master filter or disconnecting all other internal wiring so that only a single jack point remains connected for the xDSL modem.

So how much faster will my broadband be with a master filter? That’s a tough question to answer, because the results are going to depend entirely on the condition of your existing wiring. It’s very rare for a master filter to not increase broadband speeds by a minimum of 5 to 10%. It’s entirely realistic in circumstances where wiring is very poor to see speed double, or even triple. While certainly not the norm, I’ve installed master filters that have resulted in speeds going from under 5Mbps to in excess of 15Mbps. Based upon the vast number of threads on Geekzone where internal wiring is discussed and on statistics gathered from a recent project undertaken by a major ISP looking at the internal wiring issue, it’s safe to pick a modest median speed increase in the vicinity of 20% to 50%.

Most people would have never heard of a master filter, but they’re actually nothing new. When ADSL was first deployed by Telecom in the late 90’s a master filter was a mandatory requirement for an installation. To transform ADSL into a mass market product this requirement were lifted in favour of plug in filters. In many ways this made sense from a marketing view – the cost of a technician having to visit before broadband could be connected was something that would have seriously impacted take up of broadband services. This practice has still continued today and most new connections are DIY modem installs within the home.

All ISP’s as part of the sign up process for broadband can request that Chorus visit the premises and install either a master filter or install a new connection to a new jack point solely for the xDSL modem. In the vast majority of cases this doesn’t happen, primarily because the average home or business owner is going to baulk at the cost of doing this, which ranges from $199 right up to $400 depending on the work required and the connection type. This cost is too high for ISP’s to absorb on the average low margin residential broadband plan, and the average homeowner sees it as an unnecessary cost, in part because they have no idea what it’s actually achieving.

With VDSL2 services the installation of a master filter or dedicated jack point isn’t just a nice to have, it is essential. The greater frequency ranges used by VDSL2 (8Mhz for a standard 8b profile or 17MHz for a 17a profile) result in significant degradation of performance even with minor wiring issues. ISP Snap! made the decision to deploy VDSL2 as a mass market offering with no requirement for this, and anecdotal evidence shows that many users are receiving connection speeds well below what they should be receiving. A downside of this is that users with poor connections are also theoretically able to impact on the performance of other xDSL users. VDSL2 uses UBPO (upstream back-off power) to regulate the modem power output to minimise cross talk. Cross talk is essentially interference that occurs within a multi pair MPF (which can easily be several hundred lines connecting your premises back to the exchange or cabinet) where one cable pair causes interference to other nearby cable pairs. A poor VDSL2 connection results in the modem increasing it’s transmit power to attempt to compensate, which can cause cross talk, and ultimately affect other xDSL connections in the same multi pair MPF closer to the cabinet or exchange.

While I’ve explained how a master filter makes a difference I also want to show some technical data showing the differences between good and poor connections. All ISP’s have access to a tool known as SPM within the Chorus system that displays a myriad of graphs and statistics that are helpful in diagnosing xDSL connection issues. 

The image below shows a SNR capture of a good VDSL2 connection running on a standard 8b 8MHz profile off a Chorus ISAM several hundred metres from the cabinet. This line is synced at around 45Mbps downstream and 10Mbps upstream. You can see the performance of the individual carriers across the bottom of the table, referred to as tones in the following images.

vdsl2 snr

Now lets show a SNR graph of a poor quality VDSL2 connection, also off a Chorus ISAM, but being subjected to significant degradation due to wiring issues. You can see the SNR levels across the entire frequency range are lower due to the distance, and between tones 1100 and 1200 there is a large gap that is rendering this section of spectrum unusable, hence the poor upstream performance. The 2nd downstream block also has very low SNR, which ultimately means  a limited ability to carry data, which limits overall downstream performance.

vdsl2 snr poor

I’ll compare these two connections further with bit loading graphs of both connections. First off the picture below shows the 45Mbps / 10Mbps VDSL2 connection. As you can see there is good performance across the board.

vdsl2 bitloading


And below the 20Mbps / 5Mbps connection. You can very clearly see the gap in the upstream band, and also the very poor performance in the 2nd downstream band.

vdsl2 bitloading poor


I’ll now show an example of a before and after bit loading and SNR graphs where a master filter has been installed on an existing ADSL2+ connections to improve the performance. This connection is located approximately 2km from an exchange and had an ADSL2+ sync rate of 696kbps upstream and 5360kbps downstream prior to a master filter being installed.





As you can see from these images the connection is very poor, with the section of spectrum from tones 350 upward being unusable which is significantly impacting downstream performance.

What follows below are results from this same line after the installation of a master filter. The result was an increase of the ADSL sync speeds to 989kbps upstream and 10444kbps downstream. This has meant the customer’s downstream speed has close to doubled, and their upstream speed has increased by nearly 50%.





Now that I’ve explained the impact of internal wiring, how can you tell if it’s  impacting your connection? Chorus have a brilliant web based tool that will show ADSL, ADSL2+ and VDSL2 availability to any address in New Zealand. It also shows those areas that are within a 10Mbps zone – in effect around 85% of the premises in the country.

If you’re in a 10Mbps zone you will typically have a modem sync speed of at least 10Mbps. Testing to sites such as isn’t a smart way of diagnosing your connection, the best approach is to log into your modem and view the connection statistics. These are easily viewable within most modems and will look something like the following


So how do I go about getting a master filter installed?

Your ISP can arrange a master filter installation which will be performed by Chorus at a fixed cost of approximately $199. Installation can also be performed by anybody competent with installing phone wiring, with the cost varying depending on the complexity of your home wiring.

My personal view is that every home in New Zealand that has a xDSL connection should have a master filter fitted. As harsh as it sounds, If I ran Chorus I would also refuse to investigate any speed or connection related issues that end users lodge with their ISP until the end user committed to the installation of a master filter. The simple reality is that premises with multiple jack points and a xDSL connection that doesn’t have a master filter has degraded performance – while this degradation could only be minor, it could also be very significant. The issues caused by series wiring are well known, and these issues need to be eliminated to ensure the best possible connection.

Are Vodafone NZ holding NZ's best kept secret?

By Steve Biddle, in , posted: 29-Jan-2013 14:19

If you've upgraded your iPhone5 to iOS 6.1 this morning you'll now see a new setting in the network settings screen:

iOS devices need to have the carrier pack configured to allow LTE on supported networks before LTE can be used. This option will only show in phones that have had the carrier pack set to allow LTE. Vodafone New Zealand isn't listed as an official LTE carrier on the Apple website but it would be safe to assume that Apple aren't going to ruin things for Vodafone and announce something before Vodafone themselves do.

So what secret are Vodafone holding from us?

It's no secret they've just upgraded over 400 cellsites around the Auckland region over the weekend to deliver 900 MHz Dual Carrier 3G services across the Auckland region (I wrote about this here on Friday). Vodafone also have plenty of 1800MHz spectrum to deploy a LTE network on.

Does this hardware support a technology they haven't yet told us about? You decide...

Vodafone's Auckland mobile network upgrade

By Steve Biddle, in , posted: 25-Jan-2013 21:29

Vodafone announced at the start of December they were upgrading 400 cellsites in the Auckland region, and have been updating this on a weekly basis on their website.

These upgrades are now complete and the upgraded sites go live this weekend. You're probably now wondering - what is the upgrade?

Vodafone have upgraded roughly 400 sites to deliver a 900Mhz Dual Carrier 43.2Mbps 3G network across the entire Auckland region. Vodafone have used the 900Mhz band to deliver 3G coverage in rural areas of New Zealand for the last 3 years, but in the big cities, up until now, only the 2100Mhz band had been used for 3G. Why you ask? Because when Vodafone deployed their 3G network in 2005 the 2100Mhz band was the only frequency band ratified for 3G services globally. It wasn't until the 900MHz band was ratified that Vodafone were able to use the 900MHz band for 3G services, and they were one of the first networks in the world to start using the 900Mhz 3G band in 2008.

As many of you will know, signal propagation of the 2100MHz band isn't great, which has meant that inbuilding coverage on this band has always been sub optimal. 900Mhz 3G will mean that their 3G coverage will be significantly better. As the new 900MHz 3G network will all be Dual Carrier 43.2Mbps, it will add significant capacity to their their network of existing 2100MHz 3G sites, many of which are already Dual, Triple, or in some cases, Quad carrier.

This upgrade also means Vodafone instantly have a huge network advantage over Telecom. While Telecom already use the 850Mhz band for their mobile network nationwide, Vodafone have had the downside that they needed considerably more cellsites than Telecom to deploy their 2100MHz 3G network. This downside has now turned into a massive bonus for Vodafone - because the vast majority of these sites now have 900MHz 3G, Vodafone have around double the number of cellsites Auckland region using the 900Mhz band than what Telecom do using 850Mhz. This should offer Vodafone a significant inbuilding coverage advantage over Telecom.

To take advantage of the 900MHz 3G network you will need a handset that supports this band. Virtually every 3G handset sold by Vodafone or 2degrees over the last 3 or so years supports this band. Don't confuse 900Mhz with 900MHz GSM though - the 900MHz GSM network still continues to operate as usual, and a phone that doesn't mention 900Mhz 3G support in the specs, and only 900Mhz GSM isn't going to be able to benefit from this upgrade.

If you're a Vodafone user it would be interesting to hear your feedback after the upgrade goes live this weekend.

(And just for the record before somebody accuses me of being a Vodafone fanboi, I don't work, and have never worked for Vodafone)

Are pharmacies NZ’s biggest* rort? (*excluding airport carparking)

By Steve Biddle, in , posted: 21-Jan-2013 11:31

Example A - $12.99 vs $20.00 for the identical tablets at two different pharmacies.

If you do suffer from hayfever I highly recommend Levrix tablets, I've found them amazing. It might just pay however to check the price before you buy them.

levrix (Medium)

Credit Card Security–Why close enough isn’t good enough

By Steve Biddle, in , posted: 4-Jan-2013 18:28

Credit card security isn't a laughing matter these days. It's certainly not difficult to find people who have had their credit cards compromised and fraudulent transactions charged to their account. Typically this has been as a result of physical  card security being compromised by the use of a card skimmer attached to an ATM (numerous instances in Auckland), a compromised EFTPOS terminal recording card details (a major burger retailer in Queen St, Auckland), or by staff who have access to credit card records randomly copying numbers down for use (a foreign call centre for a major telco). Banks have complex systems monitoring transactions in real time and will often detect card fraud and put a hold on your card well before you're even aware there could be an issue. While card fraud normally doesn't leave the card holder out of pocket due the liability limits banks have in their terms and conditions, having to get a new card can often be a real pain if you have automatic payments such as bills set up on it.

Having had my card compromised while in Australia in the middle of 2012 and then spending an entire afternoon dealing with the consequences while trying to enjoy a relaxing long weekend away means I have zero tolerance to anybody in the industry dealing with credit cards who isn't willing to comply with industry guidelines. As far as I'm concerned you deserve to be named and shamed if you're accepting credit cards and failing to comply with industry guidelines.

The Payment Card Industry (PCI) Security Standards Council are responsible for creating data security standards for cardholder data. Known as the PCI Data Security Standard (DSS) this document covers the requirements and security assessment procedures that should be used in the banking and payments industry to ensure that card security remains a top priority. It's common to refer to being "PCI complaint" when your systems are complaint with this standard.

It's therefore surprising so see a large business like Wellington Airport failing to comply with industry PCI standards governing credit card security, and more so the fact this lack of security has now existed for several years in their car park ticketing machines.

Despite what some may think, a credit card number, or Primary Account Number (PAN) as it's technically known as, isn't just sixteen random numbers. Each card issuer has a unique Bank Identification Number (BIN) which comprises the first six digits of the card. The next nine digits are the account number, and the last digit is a check digit calculated using the MOD 10 algorithm, otherwise known as the Luhn Algorithm, calculated off the prior fifteen digits. This algorithm isn't complex, and it's easy to calculate this check digit with a piece of paper and a pen.

PCI DSS requirement 3.3 covers the storage and use of PAN numbers

3.3 Obtain and examine written policies and examine displays of PAN (for example, on screen, on paper receipts) to verify that primary account numbers (PANs) are masked when displaying cardholder data, except for those with a legitimate business need to see full PAN.

Mask PAN when displayed (the first six and last four digits are the maximum number of digits to be displayed).

As you can see the PCI DSS requirements are that the first six and last four digits are the only digits that should be displayed on a receipt. Why? Because displaying any more than this leaves your card number open to being compromised.

The first six digits are unique to your bank, so displaying these poses no real security risk. The last digit is a check digit, and the prior three prior digits are only 1/3 of your account number. Using a MOD10 calculator to calculate the remaining six digits still leaves a vast number of possibilities, so many in fact, that it poses no great security risk.

Wellington Airport receipts display the last six digits of the PAN, as pictured below (I've crossed two out so you can't see them). This now only leaves four digits that need to be generated, and literally leaves only a handful of possibilities for the card number. For all intent purposes you may as well be displaying the full PAN, as a card card can be compromised with access to the first six digits and the last six digits of the PAN.


A Wellington Airport parking receipt by itself isn't going to let somebody exploit your credit card - as they're only displaying the last six digits of the PAN. Combined with another receipt from a PCI compliant terminal or retailer however and your card number can be compromised. Considering many people throw receipts away together it's entirely possible that somebody could gain access to two receipts which would enable them to reconstruct your credit card number.

So a small tip from me - if you use your credit card at Wellington Airport be careful what you do with your receipt. It could be the most expensive car park you ever use!


Update 05/01/2012 :

Fellow Geekzone Moderator Nate spent some some time whipping up some code using the MOD 10 algorithm to generate possible card combinations. By entering an incomplete credit card number and X's to signify the masking all possible full PAN numbers are displayed. These could then easily be submitted automatically to a payment gateway to establish the valid number. If PCI compliant PAN masking of six digits is followed the 100000 possible combinations make this a a virtually impossible task. With non PCI compliant PAN masking such as that used by Wellington Airport this could be done in a matter of minutes with access to appropriate payment gateways.

More photos of the day

By Steve Biddle, in , posted: 22-Nov-2012 08:24

Photo of the day

By Steve Biddle, in , posted: 21-Nov-2012 21:48


I couldn't help but notice some new equipment staring to appear on a handful of Telecom sites around the Hutt Valley. I wonder if they're redeploying their AMPS network again? Smile

Hint: It's not the 2100MHz panel on the left or the 850MHz panel on the right.

EDIT: As of the 6th December Telecom have officially announced their LTE trial. More details are here

Ultra Fast Broadband (UFB) for Dummies.

By Steve Biddle, in , posted: 15-Nov-2012 08:11

Unless you’ve been living on another planet you’ll be aware that New Zealand is currently in the process of deploying a nationwide Fibre To The Home (FTTH) network. This network is being supported by the New Zealand Government to the tune of roughly NZ$1.5 billion over the next 10 years and is being managed by Crown Fibre Holdings (CFH). Work is presently underway deploying fibre nationwide, with several thousand homes now connected to this new network.

Much has been made of UFB retail pricing, and for many individuals and businesses the price they will pay for a UFB fibre connection could be significantly cheaper than existing copper or fibre connections. What does need to be understood however is the differences between fibre connection types, and pricing structures for these different services. There have been a number of public discussions in recent months (including at Nethui in July) where a number of comments made by people show a level of ignorance, both at a business and technical level, of exactly how fibre services are delivered, dimensioned, and the actual costs of providing a service.

So why is UFB pricing significantly cheaper than some current fibre pricing? The answer is pretty simple – it’s all about the network architecture, bandwidth requirements and the Committed Information Rate (CIR). CIR is a figure representing the actual guaranteed bandwidth per customer, something we’ll a talk lot about later. First however, we need a quick lesson on network architecture.

Current large scale fibre networks from the likes of Chorus, FX Networks, Citylink and Vector (just to name a few) are typically all Point-to-Point networks. This means the physical fibre connection to the Optical Network Terminal (ONT) on your premises is a dedicated fibre optic cable connected directly back to a single fibre port in an aggregation switch. Point-to-point architecture is similar to existing copper phone networks throughout the world, where the copper pair running to your house is dedicated connection between your premises and the local cabinet or exchange, and is used only by you. Because the fibre is only used by a single customer the speed can be guaranteed and will typically be dimensioned for a fixed speed, ie if you pay for a 100Mbps connection your connection will be provisioned with a 100Mbps CIR and this speed will be achieved 24/7 over the physical fibre connection (but once it leaves the fibre access network it is of course up to your ISP to guarantee speeds). Speeds of up to 10 Gb/s can easily be delivered over a Point-to-Point fibre connection.

The core architecture of the UFB project is Gigabit Passive Optical Network (GPON). Rather than a fibre port in the Optical Line Terminal (OLT) being dedicated to a single customer, the single fibre from the port is split using a passive optical splitter so it’s capable of serving multiple customers . GPON architecture typically involves the use of 12, 24 or 32 way splitters between the OLT and the customers ONT on their premises. GPON delivers aggregate bandwidth of 2.488Gb/s downstream and 1.244 Gb/s upstream shared between all the customers who are connected to it. 24 way splitters will typically be used in New Zealand, meaning that 100Mbps downstream and 50Mbps upstream can be delivered uncontended to each customer. The difference is architecture is immediately clear – rather than the expensive cost of the fibre port having to be recovered by a single customer as is the case with a Point-to-Point network, the cost is now recovered from multiple customers. The real world result of this is an immediate drop in the wholesale port cost, meaning wholesale access can now be offered at significantly cheaper price points than is possible with a Point-to-Point architecture. GPON’s shared architecture also means that costs can be lowered even further since the architecture of a shared network means dedicated bandwidth isn’t required for every customer like is is with a Point-to-Point connection. The 2.488Gbps downstream and 1.244Gbps upstream capacity of the GPON network instantly becomes a shared resource meaning lower costs, but it can also mean a lower quality connection compared to a Point-to-Point fibre connection.

Now that we’ve covered the basics of architecture we now need to learn the basics of bandwidth dimensioning. Above we learnt that a CIR is a guaranteed amount of bandwidth available over a connection. Bandwidth that isn’t guaranteed is known as an Excess Information Rate (EIR). EIR is a term to describe traffic that is best effort, with no real  world guarantee of performance. The 30Mbps, 50Mbps or 100Mbps service bandwidth speeds referred to in UFB residential GPON pricing are all EIR figures, as is the norm with residential grade broadband services virtually everywhere in the world. There are is no guarantee that you will receive this EIR speed, or that the speed will not vary depending on the time of the day, or with network congestion caused by other users. With Voice Over Internet Protocol (VoIP) replacing analogue phone lines in the fibre world, guaranteed bandwidth needs to also be available to ensure that VoIP services can deliver a quality fixed line replacement. To deliver this UFB GPON residential plans also include a high priority CIR of between 2.5Mbps and 10Mbps which can be used by tagged traffic. In the real world this means that a residential GPON 100Mbps connection with a 10Mbps CIR would deliver an EIR of 100Mbps, and a guaranteed 10Mbps of bandwidth for the high priority CIR path.

Those of you paying attention would have noticed a new word in the paragraph above – tagged. If you understand very little about computer networking or the internet you probably just assume that the CIR applies to the EIR figure, and that you are guaranteed 10Mbps on your 100Mbps connection. This isn’t quite the case, as maintaining a CIR and delivering a guaranteed service for high priority applications such as voice can only be done by policing traffic classes either by 801.2p tags or VLAN’s The 802.1p standard defines 8 different classes of service ranging from 0 (lowest) to 7 (highest). For traffic to use the CIR rather than EIR bandwidth it needs to be tagged with a 802.1p value within the Ethernet header so the network knows what class the traffic belongs to. Traffic with the correct high priority 802.1p tag will travel along the high priority CIR path, and traffic that either isn’t tagged, or tagged with a value other than that specified value for the high priority path will travel along the low priority EIR path. Traffic in excess of the EIR is queued, and traffic tagged with a 802.1p high priority tag that is in excess of the CIR is discarded.

For those that aren't technically savvy an analogy (which is similar but not entirely correct in every aspect) is to compare your connection to a motorway. Traffic volumes at different times of the day will result in varying speeds as all traffic on the motorway is best effort, in the same way EIR traffic is best effort. To deliver guaranteed throughput without delays a high priority lane exists on the motorway that delivers guaranteed speed 24/7 to those drivers who have specially marked vehicles that are permitted to use this lane.

There are probably some of you right now that are confused by the requirement for tagged traffic and two different traffic classes. The simple reality is that different Class of Service (CoS) traffic profiles are the best way to deliver a high quality end user experience and to guarantee Quality of Service (QoS) to sensitive traffic such as voice. Packet loss and jitter cause havoc for VoIP traffic, so dimensioning of a network to separate high and low priority traffic is quite simply best practice. Performance specifications exist for both traffic classes, with high priority traffic being subject to very low figures for frame delay, frame delay variation and frame loss.

UFB users on business plans also have a number of different plan options that differ quite considerably to residential plans. All plans have the ability to have Priority Code Point (PCP) transparency enabled or disabled. With PCP Transparency disabled, traffic is dimensioned based on the 802.1p tag value in the same way as residential connections are. With PCP Transparency enabled, all traffic, regardless of the 802.1p tag, will be regarded as high priority and your maximum speed will be your CIR rate. As the CIR on business plans can be upgraded right up to 100Mbps, GPON can deliver a service equivalent to the performance of a Point-to-Point fibre connection. Business users also have the option of opting for a CIR on their EIR (confused yet?). This means that a 100Mbps business connection can opt for a service bandwidth of 100Mbps featuring a 2.5Mbps high priority CIR, a 95Mbps low priority EIR, and a 2.5Mbps low priority CIR. This means that at any time 2.5Mbps will be the guaranteed CIR of the combined low priority traffic. The high priority CIR can be upgraded right up to 90Mbps, with such an offering delivering a 90Mbps high priority CIR, 7.5Mbps low priority EIR, and 2.5Mbps low priority CIR.

You’re now probably wondering about 802.p tagging of traffic. For upstream traffic this tagging can be done either by your router, or any network device or software application that supports this feature. Most VoIP hardware for example already comes preconfigured with 802.1p settings, however these will need to be configured with the required 802.1p value for the network. Downstream tagging of traffic introduces whole new set of challenges – while ISP’s can tag their own VoIP traffic for example, Skype traffic that may have travelled from the other side of the world is highly unlikely to contain a 802.1p tag that will place it in the high priority CIR path, so it will be treated as low priority EIR traffic. ISP’s aren’t going to necessarily have the ability to tag traffic as high priority unless it either originates within their network, or steps are taken to identify and tag specific external traffic, meaning that the uses of the CIR for downstream will be controlled by your ISP.

It is also worth noting that all of the speeds mentioned in this post refer only to the physical fibre connection. Once traffic leaves the handover point, known as an Ethernet Aggregation Switch (EAS) it’s up to the individual ISP to dimension backhaul and their own upstream bandwidth to support their users.

As part of their agreement with CFH, Chorus dropped their Point-to-Point fibre pricing in fibre existing areas in August 2011 to match UFB Point-to-Point pricing, which means customers currently in non UFB areas will pay exactly the same price for a Point-to-Point fibre access as they will do in a UFB area if they choose a Point-to-Point UFB connection. UFB GPON fibre plans won’t be available in existing fibre however areas until the GPON network has been deployed, either by Chorus or the LFC responsible for that area. In all UFB areas both GPON and Point-to-Point connections will ultimately be available.

I hope that this explains the architecture of the UFB network, and how connection bandwidth is dimensioned. It’s not necessarily a simple concept to grasp, but with the misinformation that exists I felt it was important to attempt to write something that can hopefully be understood by the average internet user. The varying plan options and pricing options means that end users have the option of choosing the most appropriate connection type to suit their needs, whether this be a high quality business plan with a high CIR, or a lower priced residential offering that will still deliver performance vastly superior to the ADSL2+ offerings most users have today.

And last but not least I have one thing to add before one or more troll(s) posts a comment saying fibre is a waste of time and complains about not getting it at their home for another 5 or 6 years. UFB is one of NZ’s largest ever infrastructure projects, and to quote the CFH website:

“The Government’s objective is to accelerate the roll-out of Ultra-Fast Broadband to 75 percent of New Zealanders over ten years, concentrating in the first six years on priority broadband users such as businesses, schools and health services, plus green field developments and certain tranches of residential areas (the UFB Objective).”

Residential is not the initial focus of the UFB rollout, and never has been. Good things take time.

Raspberry Pi – the ultimate home Asterisk PBX.

By Steve Biddle, in , posted: 21-Oct-2012 20:23

Unless you're a tech geek who's been living on another planet for the last six months you would have heard of the Raspberry Pi. If you have been living on another planet and haven't heard of it my advice is to Google it and drool, because it's safe to say the Raspberry Pi is without a doubt one of the coolest gadgets to hit the tech world in the past few years.

Stock of the Raspberry Pi has been hard to come by in recent months with demand far exceeding supply, but a new 512MB model is now out as an upgrade to the older 256MB model and stock is once again available. I ordered mine this week from Element14 in Sydney and received it the very next day. As I type this they still have stock available so if you're wanting one it'll be the best NZ$48 you've ever spent!

As I'm a VoIP guy for my day job and have been playing with Asterisk since 2004, one thing I was keen to do was deploy Asterisk and put what has to be the world's smallest PBX though it's paces. Rather than take the long process of installing Debian and Asterisk manually I thought I'd try the Incredible Pi PBX, an Asterisk / FreePBX distribution put together by Ward Mundy who's also behind PIAF, which is in my opinion the best Asterisk "all in one" distribution around.

raspberry pi


The Incredible Pi can be downloaded from here. As I'm writing this version 3.5 has just been released and I wouldn't recommend installing any older version of the software. Once you've downloaded the software you'll need to burn the image file onto your SDHC card (I recommend Image Writer if using Windows) The image requires a minimum of a 4GB card, if you opt for a bigger card the file system can easily be expanded after installation.

Once the image has been copied to the SHDC card you're ready to go. Pop the card into your Raspberry Pi and power it on. After a few seconds you'll see the boot screen and then be presented with a Debian login. To access the PBX from your console login or SSH the login is 'root' and password is 'raspberry'. To access the FreePBX web interface use the login 'admin' and password 'admin'. Congratulations. You've now got the world's coolest, smallest PBX!

I'm not doing to bore you all with a step by step guide on configuring Asterisk, but there is one catch to be aware of for anybody else in New Zealand. A FreePBX module called Astridex is installed by default and will intercept any calls routed out that start with 00. Manually edit extensions_custom.conf and remove the custom context that exists for this or any international calls starting with 00 will not work correctly.


Minimising the global roaming rort

By Steve Biddle, in , posted: 23-Aug-2012 20:53

Mobile roaming is great. The concept of being able to take your phone to over 200 countries around the world and seamlessly stay in touch with the same phone number is a wonderful concept, but it does come at a cost – a cost many believe is excessive. Regulators around the world have struggled to contain what can only be described as a global rort, with carriers around the world charging customers roaming on their networks much, much more than they do their own customers. Why? The only seemingly plausible explanation for this excessive charging? Because they can.

I’ve spent many, many thousands of dollars on mobile roaming in my travels around the world over the years and probably contributed to the bonuses paid to many BellSouth and Vodafone employees (so you’re more than welcome to shout me a coffee if you want). I’ve always known what the pricing has been, but have chosen to use roaming due to the convenience it offers. In recent years I’ve also used foreign SIM cards while roaming, in countries I visit often such as Australia I carry two phones with me.

We all know roaming is expensive, but there are plenty of tips to save money while roaming. Firstly ensure that you’re on the right plan. Telecom and 2degrees only offer a single roaming plan, this plan charges the same for calls back to New Zealand as it does for calls within the country you’re in. You pay a base rate for the country you're in and then pay the standard per minute rate that applies to calls in NZ on top of this. SMS messages cost a standard 80c to send no matter where you are, and roaming forward inbound calls cost $1 per minute to answer (the exception to these price points are Inmarsat backhauled satellite services such as on planes and cruise ships). Vodafone on the other hand offer two different roaming options, their Traveller plan works in the same way as the plan from Telecom and 2degrees, but their Standard roaming plan differentiates between calls within a country and calls back to New Zealand. Vodafone charge the same 80c per SMS and $1 per minute for inbound roam forward calls regardless of the plan.

If you’re a Vodafone customer and sign up to roaming you’ll automatically be placed on the Traveller plan, however this may not necessarily be your best option. If most of your calls are within the country you’re visiting rather than back to New Zealand you’ll be paying significantly more than you need to for calling, as an example while roaming in Hong Kong a call within Hong Kong on Traveller will cost you $3.00 per minute + your NZ airtime rate, so you're looking at around $3.40 - $3.70 per minute for that call. On the Standard roaming plan this will cost $1.00 per minute. In every destination except Australia the cost of receiving a call ($1 per minute) is cheaper than making an outbound call back to New Zealand, so for many the best option is to select the Standard plan and get people in New Zealand to call you rather than making a call from your mobile back to New Zealand.

Because Telecom and 2degrees only offer the single zone based roaming plans, significant savings can be made by switching to Vodafone if you roam regularly.

One thing that has caught my attention over the years has been a gradual increase of pricing, I thought it would be interesting to compare BellSouth’s February 1998 roaming pricelist to the prices charged by Vodafone today.When looking at this pricing it’s worth noting that inbound roam forward calls were billed in minute+second intervals rather than the minute+minute billing applied by Vodafone, Telecom and 2degrees today. Minute+minute accounts for an approximate 20% - 25% price increase over minute+second billing. Not long after this pricelist came out BellSouth also introduced offpeak and peak rates for the roaming inbound rate, meaning it cost 49c per minute to answer a call in major countries such as Australia and the UK during the New Zealand offpeak rating period (7pm to 7am and on weekends).

This pricelist also doesn’t feature SMS charges and I’m unable to locate my later pricelist that lists this, however SMS pricing was a surcharge on top of the rate you paid in New Zealand, ie 20c + surcharge. In most countries this surcharge was between 20c and 60c, so the cost of sending an SMS in 1998 vs 2012 was cheaper in many cases than it is now where a blanket 80c charge applies.

For the following table Traveller rates are the Traveller zone rate + your standard calling plan price for calls in NZ (ie somewhere in the vicinity of 40c - 70c per minute). Since prices don't differ now between networks as they did in 1998 I have only listed the price once per country.

Country 1998 Cost to answer1998 National Call1998 call to NZ2012 National
2012 Call to NZ2012 Traveller + your rate
Optus$1.04$1.05$2.20$0.50$2.00$NZ rate
Vodafone $1.04$1.00$2.35 ($5.60 for data)    
Max Mobil$2.56$1.05$2.85$2.00$6.00$2.00 +
Mobilkom $2.56$0.85$2.75   
Mobistar $2.56$0.90$4.60$2.00$6.00$2.00 +
MobilTEL$2.85$1.00$6.20$2.00$6.00$2.00 +
CYTA$2.56$0.25$4.25$1.00$4.00$2.00 +
Czech Republic:       
EuroTel Praha$2.85$0.80$6.20$1.00$6.00$2.00 +
RadioMobil (Paegus)$2.85$0.75$6.95   
Sonofon$2.56$0.85$5.45$1.50$5.00$2.00 +
Tele Denmark$2.56$0.80$5.00   
EMT$2.56$0.80$4.95$1.50$6.00$2.00 +
Radiolinja Eesti$2.56$0.75$5.50   
Vodafone $1.65$0.85$3.95$2.00$4.00$3.00 +
Oy Radiolinga AB$2.56$0.65$3.30$1.00$4.00$2.00 +
Telecom Finland $2.56$0.55$3.80   
France Telecom$2.56$1.00$3.20$1.50$5.00$2.00 +
De TeMobil D1$2.56$1.75$3.25$1.50$5.00$2.00 +
Mannesman Mobilfunk GMBH $2.56$2.05$3.95   
Gibtel $2.85$1.00$4.60$1.00$3.00$2.00 +
Panafon$2.85$1.20$4.60$1.00$3.00$2.00 +
Stet Hellas $2.85$1.15$4.50   
Guernsey Telecoms$1.80$1.16$3.30$1.00$4.00$2.00 +
Hong Kong:       
HK Telecom CSL $2.50$0.55$2.50$1.00$4.00$3.00 +
Pannon$2.56$0.75$3.25$1.00$4.00$2.00 +
Westel 900$2.56$0.70$2.60   
Pt Excelcomindo$2.56$2.35$4.75$1.00$6.00$3.00 +
Telkomsel $2.56$1.30$4.20   
Eircell $2.56$0.80$3.60$1.00$5.00$2.00 +
Esat Digifone$2.56$0.80$4.60   
Isle of Man:       
MANX Telecom$2.05$0.60$3.60$1.00$4.00$2.00 +
OmniTel$2.56$0.80$5.15$1.50$5.00$2.00 +
Telecom Mobile $2.56$0.95$5.20   
Jersey Telecoms$1.80$0.75$2.75$1.00$4.00$2.00 +
MTC$2.85$0.25$3.75$3.00$6.00$3.00 +
LMT$2.56$1.00$8.00$1.00$6.00$2.00 +
FTML$2.85$0.90$9.90$1.50$4.00$3.00 +
LibanCel $2.85$0.85$9.00   
SwissCom$2.56$1.25$3.50$2.00$6.00$2.00 +
P&T $2.85$1.20$6.65$2.00$5.00$2.00 +
CTM $3.01$0.50* $2.45$1.00$4.00$3.00 +
Biniarang (MAXIS) $2.43$1.25$3.20$1.00$4.00$3.00 +
Celcom $2.43$1.35$2.30   
MobilTEL (Bulgaria)$2.43$1.35$6.20$2.50$6.00$2.00 +
France Telecom$2.56$1.00$3.20$1.50$5.00$2.00 + 
Libertel $2.56$0.60$5.80$2.00$4.00$2.00 +
PTT Telecom$2.56$0.90$4.35   
Netcom$2.56$0.75$1.70$1.50$3.00$2.00 +
Telenor Molil$2.56$0.65$1.35   
Globe $2.56$0.95$4.20$1.00$5.00$3.00 +
Polkomtel$2.56$0.85$5.25$1.00$6.00$2.00 +
Telecel $2.85$1.00$5.80$1.50$6.00$2.00 +
QTel$2.56$0.37$4.55$2.50$6.00$3.00 +
Russia (Moscow)*      
MTS$2.56$1.50$10.50$3.00$6.00$5.00 +
MobileOne$2.25$0.35$2.75$1.00$4.00$3.00 +
Slovak Rep:      
EuroTel$2.82$1.10$6.00$2.00$6.00$2.00 +
Mobitel$2.56$1.10$3.60$2.00$6.00$2.00 +
South Africa:       
MTN $2.56$0.65$2.55$1.00$3.00$2.00 +
Vodacom $2.56$0.60$2.40   
Airtel$2.82$1.20$5.75$1.00$6.50$2.00 +
Telefonica Moviles$2.82$1.20$5.66   
Sri Lanka:       
MTN (Dialog)$3.31$0.75$6.40$1.00$6.00$3.00 +
COMVIQ$2.56$0.90$4.30$1.00$5.00$2.00 +
Telia Mobitel$2.56$0.95$4.25   
Swisscom $2.56$1.25$3.50$2.50$6.00$2.00 +
Chungwha $2.40$0.60$2.75$1.00$4.00$3.00 +
AIS $2.56$1.05$3.40$1.50$4.00$3.00 +
Telsim$2.85$0.90$3.70$2.00$6.00$2.00 +
Cellnet$1.80$0.80$4.55$1.00$4.00$2.00 +
Vodafone $1.80$0.90$2.95   

sbiddle's profile

Steve Biddle
New Zealand

I'm an engineer who loves building solutions to solve problems.

I also love sharing my views and analysis of the tech world on this blog, along with the odd story about aviation and the travel industry.

My interests and skillset include:

*VoIP (Voice over IP). I work with various brands of hardware and PBX's on a daily basis
  -Asterisk (incl PiaF, FreePBX, Elastix)

  -xDSL deployments

*Structured cabling
  -Home/office cabling
  -Phone & Data

*Computer networking
  -Mikrotik hardware
  -WAN/LAN solutions

*Wireless solutions
  -Motel/Hotel hotspot deployments
  -Outdoor wireless deployments, both small and large scale
  -Temporary wireless deployments
*CCTV solutions
  -Analogue and IP

I'm an #avgeek who loves to travel the world (preferably in seat 1A) and stay in nice hotels.

+My views do no represent my employer. I'm sure they'll be happy to give their own if you ask them.

You can contact me here or by email at