Tag: Network Resilience

Ookla Research™ Articles
| March 12, 2025

Cyclone Alfred Tests the Resilience of Telecom Infrastructure in Queensland, Australia

Network Resilience

Ex-cyclone caused widespread power outages across south Queensland and north New South Wales, putting the focus on Australian network resilience and the efforts of local government, utilities and telecom operators in restoring power and connectivity.

South Queensland and north New South Wales are in recovery mode after ex-cyclone Alfred made landfall over the weekend, leading to widespread flooding and power outages and severely impacted the availability and performance of telecom networks across the region. While the recovery effort is underway, we examine the impact of the ex-cyclone on Speedtest users in the region. Australia is an interesting case.

Key Takeaways:

  • Cyclone Alfred triggered a severe decline in mobile performance across all operators in Queensland. On the day the storm made landfall (early on March 8th local time), we saw a substantial uptick in outages reported on Downdetector across all mobile operators and the National Broadband Network (NBN), while median mobile download speeds declined strongly – Telstra’s dipped from 111.33 Mbps on Thursday March 6th, to a low of 51.76 Mbps on March 8th, with significant declines also observed for Optus and Vodafone.
  • Network hardening efforts and cyclone predictability appear to have helped reduce the impact on network infrastructure. In contrast to other major weather events that have impacted telecom networks, for example Storm Éowyn in Ireland and the UK, network performance in Queensland has shown a somewhat milder impact, and started to rebound quicker. The impact in Ireland was greater — with over 725,000 premises affected vs. over 450,000 in Queensland — but the predictable arrival of the cyclone combined with the targeted grant funding as part of the Mobile Network Hardening program likely played a role in Queensland ability to rebound. The program, currently in its third stage, specifically targets improved resilience and response to network outages from natural disasters.
  • The resulting impact on Starlink’s low-Earth orbit (LEO) service underscores user needs during severe network outages, and reinforces the importance of direct-to-cellular (D2C ) satellite services in outage scenarios. Cyclone Alfred reinforced the importance of planned D2C services as a “game changer,” in ensuring the continuity of connectivity during natural disasters, especially for a market such as Australia, with low population density and vast stretches of rural black spots. This comes hot on the heels of a recent government announcement that mobile operators will need to cover the bulk of the Australian continent by 2027 with voice, SMS and emergency service, as part of as revised Universal Service Obligation. Starlink Speedtest samples climbed by 166% on the day cyclone Alfred made landfall, and performance deteriorated under increased demand, highlighting the severity of the telecoms infrastructure disruptions as consumers scrambled to troubleshoot issues and turned to alternative connectivity solutions such as satellite.

Regional energy grid operator Energex, which manages the electricity grid in the parts of south Queensland hardest hit by the cyclone, reported “the greatest number of power outages in Queensland history caused by a natural disaster,” with more than 450,000 premises affected. Recovery efforts have proceeded rapidly, with 392,000 premises back online as of Wednesday March 12th. Energex forecasted that theremaining customers in the more challenging locations will have power restored by March 16th.

This cyclone, the first to hit this far south since Tropical Cyclone Zoe in 1974, has reinforced the importance of recent measures to ensure adequate communication with customers around network outages, introduced at the end of last year by the Australian Communications and Media Authority (ACMA). While outages linked to natural disasters are currently excluded from the ACMA’s rules, it has indicated it is set to examine how to incorporate these kinds of outages in future, but with a view to avoiding impact on critical communications from emergency services. In the meantime, it is clear that the Australian network operators have really stepped up their communications during the outage, and have quickly moved to start restoring connectivity to affected areas. The relatively predictable path and timing of this cyclone has aided preparatory efforts.

Downdetector users highlight the impact of Cyclone Alfred across fixed and mobile services

Analysis of Downdetector® data highlights the uptick in outage reports as Cyclone Alfred made landfall, and began to disrupt the power grid and impact telecommunications infrastructure early on Saturday local time. While Telstra saw the highest number of outage reports, Optus, Vodafone and the NBN also saw spikes in user outage reports, which as of Tuesday, March 11th had still not returned to their pre-cyclone values.

Cyclone Alfred Triggers Surge in Downdetector Network Outage Reports
Downdetector® | March 2025

Mobile users in Queensland see marked declines across all performance metrics, with network impacts continuing

The impact of the cyclone has been significant across all network operators. Optus noted a total of 419 mobile sites down, with just over 60% of those restored as of 8am AEDT on March 12th, via a combination of generators, and satellite-powered mobile base stations (SatCats). At the same time, Vodafone reported they had restored power to more than 100 mobile sites, but that 117 remained without power, of which only 15 lacked overlapping coverage. In addition, Telstra noted on X that it had been able to bring 85% of its impacted mobile sites back online as of the same timeline. The NBN, the national wholesale provider which manages the fixed broadband access infrastructure across Australia, mapped out a peak of 252,000 of its connections (both wired and FWA) impacted by the cyclone on Sunday March 9th, which by March 11th had fallen to 147,000. Network outages such as these present a dual strain: increased network load as fixed broadband outages shift traffic to mobile infrastructure, and a diminished mobile site grid due to power outages at mobile sites. Together, these factors significantly degrade mobile network performance, reducing overall network availability and pushing more subscribers into the cell edge, or into overlapping cells which will tend to have poorer performance.

Analysis of Speedtest Intelligence® data highlights the significant impact of Cyclone Alfred on mobile network performance in Queensland. Download and upload speeds have witnesses sustained declines, accompanied by increased latency and jitter across all operators in the state. While some recovery has been observed from Sunday (March 9th) onwards, all performance metrics remain materially below pre-storm levels. Outages such as this will reinforce calls for greater national roaming provision and mutual assistance in the event of outages, as outlined in the recommendations of a Parliamentary report presented following the review of Optus’ major network outage in November 2023.

Cyclone Alfred Blows Down Mobile Performance in Queensland Across All Metrics and Operators
Speedtest Intelligence® | March 2025

In addition to a decline in metrics like Consistency—designed to measure the proportion of Speedtest samples reflecting a consistent quality of experience (QoE)—the storm-induced network disruptions led to a substantial increase in failed or partially completed Speedtest sessions across all operators on the day of the storm. Similarly, the severe decline in 10th percentile performance—where aggregate download speeds fell, from a high of 9.10 Mbps on March 4th, to a low of 2.56 Mbps on March 8th. 10th percentile upload speeds plummeted to a low of just 0.24 Mbps, while latency rocketed to 293 ms—highlighting the extent of performance degradation experienced by mobile users at the bottom end of the scale.

Cyclone Alfred Triggers Deterioration in Consistency Across All Operators
Speedtest Intelligence® | March 2025

LEO satellites pick up some of the slack

While significant amounts of fixed traffic will have migrated to mobile as power outages occurred, and where mobile signal was still available, we also witnessed an uptick in Starlink Speedtest samples during the ex-cylone’s passage across southern Queensland. Starlink samples hit a high on Sunday March 9th, representing an increase of 166% over samples observed at the start of March. This additional demand on the service pushed performance levels down, hitting a low of 47.11 Mbps median download speed, but recovering swiftly afterwards.

Starlink Performance During Cyclone Alfred – Queensland
Speedtest Intelligence® | March 2025

Starlink’s performance here is interesting to observe in light of the recent Australian government announcement that all mobile providers in the country should provide near nationwide coverage for voice and SMS and Triple Zero (emergency) services by 2027, as part of the Universal Outdoor Mobile Obligation (UOMO), itself part of an updated Universal Service Obligation (USO). D2C services via LEO satellites are imminent in the country, with both Telstra and Optus having inked deals with Starlink, while Vodafone (TPG Group) has an agreement in place with Lynk Global. We will continue to monitor network resilience around the world in the face of severe network outages, and highlight best practice. For more information on how Downdetector and Speedtest can help respond to outages, detect areas of poor performance and optimise networks, please contact us.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Network Resilience

About the Author

Mark Giles

Ookla Research™ Articles
| March 12, 2025

How a Power Outage Impacted Chile’s Mobile Network Resiliency

Network Resilience
Spanish / Español

Here’s what Chile’s 12-hour nationwide power outage looked like according to mobile Speedtest data

A major transmission line failure caused a massive power outage across most of Chile. The outage began in the afternoon of February 25th and lasted approximately 12 hours, into the early morning of February 26th. Critical facilities like hospitals had to rely on backup power generators and the outage was disruptive enough that a state of emergency was declared for the country. 

How did mobile networks perform during the outage? This article looks at mobile networks’ performance through SpeedtestⓇ metrics of sample counts (i.e., the number of completed Speedtests) and download speeds. 

Ookla examined the hourly Speedtest sample counts of the main four mobile carriers in Chile over a 72-hour period. Prior to noon on February 25, 2025, the networks performed in a  normal state with fewer samples in the night and more in the day. 

The outage reportedly started at 3:16 p.m., which matches the spikes in the counts of Speedtest users checking on the network. Comparing the 12-hour outage to the same time the day before, the rate of testing was over 2.5x. This behavior is typical of, and similar to, mobile network outages seen around the world. Staying connected in an emergency is critically important, so checking the status of the network makes good sense.

By the morning of February 26, 2025, when the outage is over and power restored, there is more testing than the prior two mornings. This is likely due to many people checking their phones upon waking up, so it isn’t unusual to see more aggressive testing than usual.

How did the mobile networks perform?

When mobile networks are “unloaded” — that is, not carrying much traffic — as they usually are at night, Speedtest users clock faster speeds. These are the peaks in the chart. The valleys are the times when most people are active and more loading occurs, resulting in slower speeds. 

Selecting the 12 hours of the power outage (the labeled box) and the same 12 hours the prior day (the unlabeled box), the median download speed for the group of operators was effectively cut in half — 16.42 Mbps during the power outage compared to 33.68 Mbps before.

Taking a closer look at all the mobile service providers together, from the outage starting just after 3 p.m., median download speed initially held around 12+ Mbps, then dipped to its low point during the 6 p.m. hour at 7.49 Mbps. Thereafter and until recovery started around 11 p.m., download speeds remained in a narrow range around 9-10 Mbps through the 10 p.m hour. While these median download speeds wouldn’t be considered fast, they do suggest that the mobile networks were serviceable and customers were able to stay in touch.

However, noting that median means the middle, half of the Speedtest users were experiencing slower speeds than seen in the line chart. (And obviously, half were faster, but they wouldn’t have as poor an experience.) To get a sense of the bottom, the slowest 10th percentile for the day of the outage (February 25) compares unfavorably to the same three prior Tuesdays in February. On the day of the outage, the 10th percentile speed was below 1 Mbps – effectively unusable apart from a text message and hopefully holding a voice call. The prior three Tuesdays recorded 2.60 Mbps – still not great, but in older wireless network generations this was fast enough for watching a standard definition (SD) video.

Another observation from the closer look at All Providers Download Speed is the speed declined from early in the outage (3 p.m. to 4 p.m.) to the middle of the outage (5 p.m. to 10 p.m.). One explanation could be the network loading mentioned before, but this seems unlikely since the normal peak loading pattern would have been entirely disrupted by the power outage. A second explanation may be that backup battery power for the cell sites on mobile networks ran out. That is to say, if, for example, every site had a couple hours of battery backup, and some sites also had generators that came online after the batteries were used up, a pattern like this could be seen.

The Chilean telecoms regulator, SUBTEL, was cited in tech press to be looking into increasing the purported four-hour back up to six hours. Network hardening, whether against a power outage or other disruptions like natural disasters, is critical for network resilience.  

Ookla data can offer insights into network performance, reliability, and resiliency. To find out more about Speedtest Intelligence® data and insights, please contact us here.

Cómo afectó un apagón eléctrico a la resiliencia de la red móvil de Chile

Así fue el apagón nacional de 12 horas en Chile según los datos de Speedtest móvil

Una importante avería en una línea de transmisión provocó un apagón masivo en la mayor parte de Chile. El corte comenzó en la tarde del 25 de febrero y duró aproximadamente 12 horas, hasta la madrugada del 26 de febrero. Las instalaciones críticas, como los hospitales, tuvieron que recurrir a generadores de energía de reserva y el apagón fue tan disruptivo que se declaró el estado de emergencia en el país. 

¿Cómo funcionaron las redes móviles durante el apagón? Este artículo examina el rendimiento de las redes móviles a través de las métricas de recuento de muestras de SpeedtestⓇ (es decir, el número de Speedtests completados) y velocidades de descarga.

Ookla analizó los recuentos horarios de muestras Speedtest de los cuatro principales operadores de telefonía móvil de Chile durante un período de 72 horas. Antes del mediodía del 25 de febrero de 2025, las redes funcionaban de manera normal, con menos muestras durante la noche y más durante el día. 

Al parecer, la interrupción comenzó a las 15.16 horas, lo que coincide con los picos en los recuentos de usuarios de Speedtest que comprueban la red. Si se compara la interrupción de 12 horas con la misma hora del día anterior, la tasa de comprobación se multiplicó por más de 2,5. Este comportamiento es típico y similar al de las interrupciones de la red móvil en todo el mundo. Mantenerse conectado en caso de emergencia es de vital importancia, por lo que comprobar el estado de la red tiene mucho sentido.

En la mañana del 26 de febrero de 2025, cuando terminó el apagón y se restableció el suministro eléctrico, se registraron más test que las dos mañanas anteriores. Esto se debe probablemente a que muchas personas comprueban sus teléfonos al despertarse, por lo que no es raro ver más pruebas de lo habitual. 

¿Cómo funcionaron las redes móviles?

Cuando las redes móviles están “descargadas”, es decir, no tienen mucho tráfico, como suele ocurrir por la noche, los usuarios de Speedtest registran velocidades más rápidas. Esto es lo que representan son los picos en el gráfico. Los valles son los momentos en los que la mayoría de las personas están activas y se produce una mayor carga en la red, lo que da como resultado velocidades más lentas.

Seleccionando las 12 horas del apagón (el recuadro con la línea más gruesa) y las mismas 12 horas del día anterior (el recuadro con la línea más fina), la velocidad media de descarga del grupo de operadores se redujo efectivamente a la mitad: 16,42 Mbps durante el apagón frente a 33,68 Mbps antes.

Si analizamos todos los proveedores de servicios móviles en su conjunto, desde el apagón que comenzó justo después de las 15.00 horas, la velocidad mediana de descarga se mantuvo inicialmente en torno a los 12 Mbps o más, para descender a su punto más bajo a las 18.00 horas, con 7,49 Mbps. A partir de entonces, y hasta que comenzó la recuperación hacia las 23.00 horas, las velocidades de descarga se mantuvieron en un estrecho margen de entre 9 y 10 Mbps hasta las 22.00 horas. Aunque estas velocidades medianas de descarga no se pueden considerar rápidas, sugieren que las redes móviles estaban operativas y los clientes pudieron mantenerse en contacto.

Sin embargo, teniendo en cuenta que la mediana significa el medio, la mitad de los usuarios de Speedtest experimentaron velocidades más lentas que las que se ven en el gráfico lineal (y obviamente, la mitad eran más rápidos, pero no tendrían una experiencia tan mala). Para hacerse una idea de la parte inferior, el percentil 10 más lento para el día de la interrupción (25 de febrero) se compara desfavorablemente con los mismos tres martes anteriores de febrero. El día del apagón, la velocidad del percentil 10 estaba por debajo de 1 Mbps, prácticamente inutilizable salvo para enviar un mensaje de texto y, con suerte, mantener una llamada de voz. Los tres martes anteriores se registraron 2,60 Mbps, lo que sigue sin ser bueno, pero en las antiguas generaciones de redes inalámbricas era lo bastante rápido para ver un vídeo de definición estándar (SD).

Otra observación que se desprende del análisis de la velocidad de descarga de todos los proveedores es que la velocidad disminuyó desde el principio del apagón (de 15.00 a 16.00 horas) hasta la mitad del mismo (de 17.00 a 22.00 horas). Una explicación podría ser la carga de la red mencionada antes, pero parece poco probable, ya que el patrón normal de picos de carga se habría visto totalmente interrumpido por el apagón. Una segunda explicación podría ser que se agotaran las baterías de reserva de los emplazamientos de las redes móviles. Es decir, si, por ejemplo, cada emplazamiento tuviera un par de horas de batería de reserva, y algunos emplazamientos también tuvieran generadores que entraran en funcionamiento una vez agotadas las baterías, podría observarse un patrón como éste.

La SUBTEL, organismo regulador de las telecomunicaciones en Chile, ha sido citada en la prensa tecnológica por estudiar la posibilidad de aumentar a seis horas la supuesta reserva de cuatro horas. El refuerzo de la red, ya sea contra cortes de electricidad u otras interrupciones como catástrofes naturales, es fundamental para la resistencia de la red.  

Los datos de Ookla pueden ofrecer información sobre el rendimiento, la fiabilidad y la resistencia de la red. Para obtener más información sobre los datos y perspectivas de Speedtest Intelligence, póngase en contacto con nosotros ®aquí.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Network Resilience

About the Author

Kerry Baker

Ookla Research™ Articles
| January 27, 2025

Impact Analysis: Storm Éowyn Tests the Resilience of Telecoms Infrastructure in the UK and Ireland

Network Resilience

Record power outages have crippled mobile network infrastructure, underscoring the need for network hardening as severe weather events become more frequent.

The UK and Ireland are in recovery mode after Storm Éowyn wreaked havoc on electricity and telecoms infrastructure in recent days. With record wind gusts exceeding 180 km/h recorded in Ireland and a ‘major incident’ declared on the Isle of Man, the storm has been historic in both its strength and the extent of the damage caused across the islands.

Key Takeaways:

  • Storm Éowyn triggered a rapid, severe and sustained decline in mobile performance across all operators in Ireland and parts of the UK, particularly Northern Ireland and Scotland, on a scale not seen before. On the day the storm made landfall (24th January), median mobile download speeds in Ireland (10.04 Mbps) were 78% lower than the preceding 7-day average of 47.43 Mbps, while median latency was 23% higher at 47.6 ms. In Scotland and Northern Ireland, mobile download speeds at the 10th percentile—a critical metric reflecting the poorest network performance—dropped significantly on the same day, falling by 63% to 2.19 Mbps and by 74% to 1.31 Mbps, respectively, compared to the 7-day average. 
  • Network disruptions drove a dramatic deterioration in quality of experience (QoE) in bread-and-butter consumer applications. Consistency—an important metric indicating the proportion of Speedtest samples meeting minimum download and upload speed thresholds—dropped sharply on the day of the storm, falling by over 20 percentage points to 60.3% in Northern Ireland and by nearly 40 percentage points to 52.3% in Ireland compared to the preceding 7-day average. On the day following the storm (25th January), as power restoration efforts were still in their early stages, Video Score—a key indicator of QoE in gaming activities—remained significantly suppressed, falling by over 23 points compared to the preceding 7-day average in Northern Ireland.
  • The unprecedented scale of impact on telecoms infrastructure serves as the latest and most high-profile call to action for hardening networks against increasingly frequent and severe storms in the UK and Ireland. Record daily consumer-initiated Speedtest volumes and a 62% surge in Speedtests conducted on Starlink connections in Ireland on the storm day, compared to the preceding 7-day average, highlight the severity of the telecoms infrastructure disruptions as consumers scrambled to troubleshoot issues and turned to alternative connectivity solutions like satellite.

Ireland’s state electricity supplier, ESB Networks, reported “unprecedented” power outages affecting over 725,000 premises (equivalent to as much as one-third of all homes in the country), with restoration times expected to exceed a week in the hardest-hit areas. The extensive damage to the electricity grid has had severe knock-on effects on both fixed and mobile network infrastructure, with well over a thousand mobile sites taken offline due to disruptions to mains power and downed trees causing damage to overhead fibre cabling along roads.

The impacts have been significant across operators. In Ireland, Eir reported that fixed broadband faults were affecting 160,000 premises, with more than 900 mobile sites knocked offline, while Vodafone said more than 10% of its mobile site footprint was affected. Similarly, in the UK, there were elevated reports of network outages across telecoms operators on Downdetector, with the largest concentration of disruptions in the worst hit areas in Scotland and Northern Ireland.

This storm, the most severe to date, follows a series of disruptive weather events across the UK and Ireland during recent winter months. In December, Ookla published detailed research on the impact of Storm Darragh, highlighting the unique challenges posed by widespread, prolonged power outages on mobile networks. These challenges included a dual strain: increased network load as fixed broadband outages shifted traffic to mobile infrastructure and a diminished mobile site grid due to power outages at mobile sites. Together, these factors significantly degrade mobile network performance, reducing overall network availability and pushing more subscribers into the cell edge.

Mobile users in Ireland see marked declines across all performance metrics, with network impacts continuing

Analysis of Speedtest Intelligence® data highlights the significant impact of Storm Éowyn on mobile network performance in Ireland. Download and upload speeds saw sharp and sustained declines, accompanied by increased latency and jitter across all operators nationwide. The deterioration started early on Friday morning, 24th January, as the storm made landfall. While some recovery was observed the following day (25th January), all performance metrics remain materially below pre-storm levels nationally.

Despite the absence of active network sharing in Ireland—limited to cooperation on passive infrastructure, which relies on a common mains power supply at shared sites—the storm’s impacts were felt similarly across operators. Notably, the performance profile across operators during the storm closely mirrored pre-storm trends. For instance, Three maintained its lead in download speed and demonstrated a faster recovery on this metric compared to other operators.

Storm Éowyn Blows Down Mobile Performance in Ireland Across All Metrics and Operators
Speedtest Intelligence® | January 2025

In addition to a decline in metrics like Consistency—designed to measure the proportion of Speedtest samples reflecting a consistent quality of experience (QoE)—the storm-induced network disruptions led to a substantial increase in failed or partially completed Speedtest sessions across all operators on the day of the storm. Similarly, the severe decline in 10th percentile performance—where aggregate download speeds plummeted by over 87%, from a 7-day average of 3.97 Mbps to just 0.51 Mbps—highlights the extent of performance degradation experienced by Irish mobile users at the bottom end.

Storm Éowyn Triggers Sharp Deterioration in Consistency Across All Operators
Speedtest Intelligence® | January 2025

On the day of the storm, Consistency dropped to a low of 38% at 09:00 on Friday nationally and remained below 55% in the evening. While there was an improvement the following day (25th January), reaching a high of 66% at 16:00, the overall profile remains significantly below the pre-storm baseline.

Storm Éowyn Triggers Sharp, Sustained Decline in Consistency Across Ireland
Speedtest Intelligence® | January 2025

It is notable that the limited penetration of battery backup solutions in Ireland’s mobile site grid—typically providing only four to eight hours of power where available—stands in sharp contrast to regions like the Nordics and Australia, which have implemented comprehensive policy measures to harden telecoms infrastructure, as highlighted in a recent Ookla article. This shortfall has resulted in a disproportionate reliance on stationary and mobile generators in the Irish context.

While mobile generators have high operating costs, which limit their feasibility for prolonged or widespread deployment across the mobile site grid in Ireland, they offer operators valuable deployment flexibility. Mobile operators can proactively position generators at key sites based on forecasted storm tracks and leverage distributed fuel dumps across the country to enable rapid refueling during post-storm operations.

Analysis of Speedtest Intelligence data underlines the impact of these efforts on service continuity and restoration. On the morning of the storm, Eir publicly reported deploying mobile generators to key sites in County Cork—one of the worst-affected areas—to restore mobile services ahead of mains power being restored. This proactive approach (which all operators adopted) is reflected in a sharp recovery of Eir’s Consistency score in Cork, which rebounded from as low as 59% on the day of the storm to as high as 95% the following day. This rate of recovery outpaced other operators in the county for this metric, highlighting the important role of rapid power restoration using generator solutions.

Mobile network disruptions extend to Scotland and Northern Ireland

While Ireland experienced some of the most severe and widespread impacts of Storm Éowyn, it was not alone. In Northern Ireland, power outages affecting 30% of premises at their peak were reported by NIE Networks, the primary energy provider in the region. Similarly, in Scotland, over 100,000 homes were left without power, with restoration efforts expected to continue for several days. These widespread power outages have impacted mobile site uptime in both regions.

Storm Éowyn's Impact on Consistency was more pronounced in Northern Ireland than Scotland
Speedtest Intelligence® | January 2025

Speedtest Intelligence data indicates a decline in mobile performance across multiple metrics among operators in Northern Ireland and Scotland, with Northern Ireland experiencing the greatest impact. Mobile download speeds at the 10th percentile plummeted on the day of the storm, falling 63% to 2.19 Mbps in Scotland and 74% to 1.31 Mbps in Northern Ireland relative to the seven-day average before the storm.

Storm Éowyn Pulls Down Mobile Performance Across Several Metrics in Scotland and Northern Ireland
Speedtest Intelligence® | January 2025

Similar to Ireland, the penetration of battery backup solutions installed at mobile sites in the UK remains limited. In its latest annual ‘Connected Nations‘ report, Ofcom noted that only around 20% of all mobile sites in the UK have some backup functionality at the RAN for more than 15 minutes, while only around 5% of sites are able to withstand a six-hour power loss (excluding battery backup for transmission traffic). It has consulted on revised ‘Resilience Guidance’ for the UK’s telecoms operators, published a call for input (CFI) on power backup for mobile networks and is now working with the government to determine if additional resilience measures are needed. 

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Network Resilience

About the Author

Luke Kehoe

Ookla Research™ Articles
| December 11, 2024

Mobile Network Resilience Under the Spotlight in Ireland During Storm Darragh

Europe

Climate change is placing new demands on operators and regulators to harden telecoms infrastructure against severe weather events

Storm Darragh caused widespread mobile network outages across Ireland in recent days, impacting all operators. The storm resulted in the most extensive damage to the country’s electricity infrastructure in a decade, leaving nearly 400,000 premises without power at its peak.

This led to significant disruptions to mobile site uptime, prompting the swift deployment of mobile generators across affected areas and a seismic shift in mobile network usage patterns, with increased demand in locations where power cuts or other disruptions rendered fixed broadband unusable.

Mobile networks came under strain during Storm Darragh, pulling down performance nationwide

Analysis of Speedtest Intelligence® data reveals the substantial impact of the storm on mobile network performance in Ireland. A marked and sustained decline in download and upload speeds, as well as increased latency and jitter, was observed across all operators nationally. The deterioration escalated rapidly on Friday night (6th December) as the storm made landfall, peaking on Saturday (7th December) and is only slowly returning to the pre-storm performance baseline as power outages persist through this week in the worst-affected areas.

Consistency Deteriorated Across All Mobile Operators in Ireland During Storm Darragh
Speedtest Intelligence® | December 2024

Median download speeds on Saturday were nearly 70% lower than the 7-day average preceding the storm across all operators and technologies, while median latency increased by nearly 17%. Consistency—a measure of the percentage of an operator’s samples meeting or exceeding minimum download and upload thresholds—dropped to some of its lowest one-day levels recorded in Ireland in recent years. Around 40% of all samples failed to meet the minimum thresholds across 4G (5 Mbps download, 1 Mbps upload) and 5G (25 Mbps download, 3 Mbps upload) on Saturday.

This performance analysis is based on the national picture, highlighting that the impact was significant enough to lower the overall country-wide performance profile. A closer examination of the worst-affected areas along the western seaboard revealed even more pronounced declines in performance outcomes in the aftermath of the storm.

Latency Performance Deteriorated Across All Mobile Operators in Ireland During Storm Darragh
Speedtest Intelligence® | December 2024


The volume of Speedtests initiated by Irish users increased significantly above typical levels over the weekend, serving as a proxy for the connectivity challenges. This surge also reflects the impact of a shift in usage patterns, with households resorting to tethering mobile connections when fixed broadband became unavailable and thereby increasing further the strain on a depleted mobile site grid.

Download Speed Performance Deteriorated Across All Operators in Ireland During Storm Darragh

Upload Speed Performance Deteriorated Across All Mobile Operators in Ireland During Storm Darragh
Speedtest Intelligence® | December 2024

10th Percentile Download Speed Performance is Recovering As Power Outages Recede and Network Load Normalises
Speedtest Intelligence® | December 2024

Battery backup is needed for future resilience but costs remain a barrier

Lead-acid and lithium-ion batteries are widely deployed across mobile sites in Ireland and other countries, providing short-term resilience in the event of power outages. The fact that only a small proportion of deployed backup batteries provide sufficient capacity to last for multiple hours means that operators rely heavily on stationary and mobile generators during prolonged power outages.

Ireland is no exception to this trend. The UK’s Ofcom reported recently that “around 20% of all mobile sites have some backup functionality at the RAN [in the UK] for more than 15 minutes, with around 5% of sites able to withstand a six-hour power loss (excluding battery backup for transmission traffic)”. It has consulted on revised ‘Resilience Guidance’ for the UK’s telecoms operators, published a call for input (CFI) on power backup for mobile networks and is now working with the government to determine if additional resilience measures are needed. 

Mobile operators in Ireland and elsewhere proactively ensure that generators are refuelled in advance of adverse weather events like Storm Darragh and leverage strategic fuel dumps across the country to enable rapid refuelling where needed. The high upfront cost of battery backup and the high operating cost of generators, however, prohibits universal deployment in the current capital environment, with dedicated solutions needed for each operator, even at shared sites—necessitating targeted policy support and new solutions to improve network resilience as the frequency and severity of these weather events increases.

Network resilience lessons from around the world

The policy success of Nordic countries such as Norway and Finland, where local regulators NKOM and Traficom have intervened with legislative instruments to stipulate a minimum number of hours of continuity of mobile service post-power outage, demonstrates that there are viable solutions to harden mobile network infrastructure. Similar efforts have been observed in Australia, where the government subsidised a ‘Mobile Network Hardening’ programme to retrofit 467 cell sites with 12 hours power backup capability.

Ofcom’s aforementioned consultations have not yet led to the proposal of any specific measures relating to the provision of battery backup solutions in the UK. The regulator’s preliminary assessment of the feasibility of any such measures concluded that the exorbitant costs involved in providing a minimum of one hour of power resilience at every cell site in the country would not be proportionate to the potential economic benefit accrued—with cost projections in the region of £0.9-1.8 billion.

Nonetheless, Ofcom has expressed hope that the continued reduction in the cost of battery backup solutions will make interventions viable in the future. Progress in developing new business models to monetise battery backup solutions is also likely to improve their allure over time for operators, with new use cases emerging in grid frequency restoration.

Finland’s Elisa has been a global leader in this space through the success of its ‘Distributed Energy Storage’ solution, which provides energy to the grid at peak times and charges from the grid in off-peak times. The operator claims to have reduced the payback period of its mobile site battery installations to 3-5 years.

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Europe
Network Resilience

About the Author

Luke Kehoe