receiving SMS messages

Dan Weatherill plasteredparrot at
Thu Aug 7 20:26:06 CEST 2008

On Thursday 07 August 2008 03:04:02 Robert William Hutton wrote:
> Dan Weatherill wrote:
> > If the phone is in standby, and I receive a text message, the phone
> > wakes up but does not receive a text message. The person sending the
> > message does, however, receive a delivery report. This occurs in both
> > images as well.
> >
> > If I then subsequently receive a message after the others, whilst the
> > phone is out of standby, I receive all the messages together. Hence, no
> > messages are "lost" in the ether, but it seems that messages received
> > whilst the phone is on standby are temporarily mislaid.
> This could be a possible explanation of what's going on:
> 1. The network attempts to send an SMS to your phone.
> 2. The GSM chip receives notification from the network that there's an SMS.
> 3. The GSM chip says to the network: wait, I'm temporarily unable to
> receive (as the phone's asleep) and wakes up the system.
> 4. The system comes up and waits.
> 5. In the meantime the network has accepted that the SMS can't be sent,
> and puts it into some kind of wait queue.
> It's up to the network what kind of exponential backoff algorithm they
> use to decide when to resend.  If the phone goes back to sleep before
> the network attempts a resend, then the same events will occur at some
> later time and the SMS will end up going back into the queue.  Again and
> again.
> On the Optus network, and from my experience with my old phone whose
> inbox filled up all the time, the time between retries can become long
> quite fast.  When a subsequent SMS is sent, this always flushes the
> retry queue as well, which is why you receive several messages at a time.
> Cheers,
> Rob.

Hi Rob (and everyone else),
I did originally think this was what was happening, but It's definitely not the 
whole picture. For one thing, the sender receives a delivery receipt even 
though the text has not arrived. Ok, I hear you say, it could still be the 
case that the network sends a delivery receipt when the text has not arrived 
at the actual handset, but just the "queue". To test this, I intend to switch 
my freerunner on, have a message sent to it whilst it is in standby, and then 
plug it in and leave it on (not standby) for about six hours. I'll let you 
know how I get on.

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