On Mon 24/04/2023 13:39, Java Jive wrote:
> On 23/04/2023 21:26, Java Jive wrote:
>> On 23/04/2023 17:04, Tweed wrote:
>>>
>>> Woody <harrogate3@ntlworld.com> wrote:
>>>>
>>>> On Sun 23/04/2023 16:45, Tweed wrote:
>>>>>
>>>>> Judging by reports, 3 failed to send the alert.
>>>>
>>>> +1
>>>
>>> Further reports suggest some, but not many, 3 sites managed to send the
>>> alert.
>>
>> I didn't get it in Sutherland.
>
> We now have some sort of explanation ...
>
> https://www.theguardian.com/society/2023/apr/24/why-did-some-people-get-the-uk-emergency-alert-late-or-not-at-all
>
> "Why did some Three users not receive the alert?
>
> Unlike in the pandemic, when SMS alerts were sent specifically to
> individual numbers, Sunday’s alert was broadcast via the mobile phone
> masts that form the core of the nation’s 4G and 5G networks. It means
> that if you were within range of a mast, you should have received an alert.
>
> However, what appears to have happened on the Three network is a
> configuration error preventing the majority of users receiving the
> alert. The “cell broadcast system” that underpins the alert is a
> fundamental part of the international standard for mobile phones, and
> the technology of mobile masts requires networks to send out the alert
> at regular intervals to ensure it is picked up by all phones. Most
> networks did just that, repeating the pulse multiple times a second for
> up to 20 minutes, to ensure that users with intermittent coverage still
> received it.
>
> But according to signal analysis, Three apparently sent the signal out
> just once, at 3pm on the dot, ensuring that only those phones that were
> actively connected to the network at exactly that millisecond received it."
>

My phone was and I didn't.......

On 24/04/2023 15:18, Woody wrote:
> On Mon 24/04/2023 13:39, Java Jive wrote:
>> On 23/04/2023 21:26, Java Jive wrote:
>>> On 23/04/2023 17:04, Tweed wrote:
>>>>
>>>> Woody <harrogate3@ntlworld.com> wrote:
>>>>>
>>>>> On Sun 23/04/2023 16:45, Tweed wrote:
>>>>>>
>>>>>> Judging by reports, 3 failed to send the alert.
>>>>>
>>>>> +1
>>>>
>>>> Further reports suggest some, but not many, 3 sites managed to send
>>>> the
>>>> alert.
>>>
>>> I didn't get it in Sutherland.
>>
>> We now have some sort of explanation ...
>>
>> https://www.theguardian.com/society/2023/apr/24/why-did-some-people-get-the-uk-emergency-alert-late-or-not-at-all
>>
>>
>> "Why did some Three users not receive the alert?
>>
>> Unlike in the pandemic, when SMS alerts were sent specifically to
>> individual numbers, Sunday’s alert was broadcast via the mobile phone
>> masts that form the core of the nation’s 4G and 5G networks. It means
>> that if you were within range of a mast, you should have received an
>> alert.
>>
>> However, what appears to have happened on the Three network is a
>> configuration error preventing the majority of users receiving the
>> alert. The “cell broadcast system” that underpins the alert is a
>> fundamental part of the international standard for mobile phones, and
>> the technology of mobile masts requires networks to send out the
>> alert at regular intervals to ensure it is picked up by all phones.
>> Most networks did just that, repeating the pulse multiple times a
>> second for up to 20 minutes, to ensure that users with intermittent
>> coverage still received it.
>>
>> But according to signal analysis, Three apparently sent the signal
>> out just once, at 3pm on the dot, ensuring that only those phones
>> that were actively connected to the network at exactly that
>> millisecond received it."
>>
>
> My phone was and I didn't.......

 Yea, but that's the whole thing about packet (rather than circuit)
based comms, in'it ?

On Mon 24/04/2023 15:48, Mark Carver wrote:
> On 24/04/2023 15:18, Woody wrote:
>> On Mon 24/04/2023 13:39, Java Jive wrote:
>>> On 23/04/2023 21:26, Java Jive wrote:
>>>> On 23/04/2023 17:04, Tweed wrote:
>>>>>
>>>>> Woody <harrogate3@ntlworld.com> wrote:
>>>>>>
>>>>>> On Sun 23/04/2023 16:45, Tweed wrote:
>>>>>>>
>>>>>>> Judging by reports, 3 failed to send the alert.
>>>>>>
>>>>>> +1
>>>>>
>>>>> Further reports suggest some, but not many, 3 sites managed to send
>>>>> the
>>>>> alert.
>>>>
>>>> I didn't get it in Sutherland.
>>>
>>> We now have some sort of explanation ...
>>>
>>> https://www.theguardian.com/society/2023/apr/24/why-did-some-people-get-the-uk-emergency-alert-late-or-not-at-all
>>>
>>> "Why did some Three users not receive the alert?
>>>
>>> Unlike in the pandemic, when SMS alerts were sent specifically to
>>> individual numbers, Sunday’s alert was broadcast via the mobile phone
>>> masts that form the core of the nation’s 4G and 5G networks. It means
>>> that if you were within range of a mast, you should have received an
>>> alert.
>>>
>>> However, what appears to have happened on the Three network is a
>>> configuration error preventing the majority of users receiving the
>>> alert. The “cell broadcast system” that underpins the alert is a
>>> fundamental part of the international standard for mobile phones, and
>>> the technology of mobile masts requires networks to send out the
>>> alert at regular intervals to ensure it is picked up by all phones.
>>> Most networks did just that, repeating the pulse multiple times a
>>> second for up to 20 minutes, to ensure that users with intermittent
>>> coverage still received it.
>>>
>>> But according to signal analysis, Three apparently sent the signal
>>> out just once, at 3pm on the dot, ensuring that only those phones
>>> that were actively connected to the network at exactly that
>>> millisecond received it."
>>>
>>
>> My phone was and I didn't.......
>
>  Yea, but that's the whole thing about packet (rather than circuit)
> based comms, in'it ?

Erm? Packet handshakes, but this was a straight 'shove it out there and
hope' affair. 8-))

Woody <harrogate3@ntlworld.com> wrote:
> On Mon 24/04/2023 13:39, Java Jive wrote:
> >
> > But according to signal analysis, Three apparently sent the signal out
> > just once, at 3pm on the dot, ensuring that only those phones that were
> > actively connected to the network at exactly that millisecond received it."
> >
>
> My phone was and I didn't.......

It sounds like it's the 'active' part that's critical. If there was a
packet going through at that exact time then you got the alert. If there
was no traffic passing in the specific millisecond you didn't, even if the
phone was turned on, showing signal ad had passed a packet the second
before. Without an active packet sniffer you wouldn't know the difference.

Sounds like a big SNAFU on the part of Three, but I suppose that's what
tests are for...

Theo