Always-on networking via GPRS

Nuutti Kotivuori naked at
Tue May 1 18:33:40 CEST 2007

Note: I am answering to a message from the community mailing list here.

Mikko Rauhala wrote:
> ti, 2007-05-01 kello 17:58 +0300, Nuutti Kotivuori kirjoitti:
>> On the actual software level, I guess this means that PPP will get
>> disconnected on voice calls, so the 'ppp0' device will go appear
>> and disappear and possibly change IP-addresses on every
>> disconnection as well. Is there any way to have the device survive
>> disconnections?
> This shouldn't be necessary (and isn't on other Class B phones),
> though is, I guess, partly a software issue (that is, is able to be
> handled badly :). As said, the GPRS just gets paused, not turned
> off, so it should merely block for a while and should be recoverable
> after voice/SMS use, at least if Neo's GPRS chip isn't somehow more
> limited than eg. an N-Gage (my current phone, was the cheapest Putty
> capable one at the time ;] ). On that phone, I can happily continue
> an existing Putty terminal session after a phone call has
> interrupted it, kinda expect to be able to do the same with the Neo.

Hmmh, okay. But, since GPRS is really blocked for the duration of the
call, doesn't that mean that the local PPP client will not get replies
to LCP echo packets? So atleast the local ppp must be configured to
never disconnect the call on LCP echo failures. What about the remote
side? Surely there must be some time after which the remote ppp will
disconnect your client for not answering to anything - or is there?

I can understand ppp surviving short phone calls - but does it really
survive 30 minutes of downtime?

>> USB-networking is probably no problem since it shows up as a normal
>> ethernet device on both ends. But how to do Bluetooth networking? One
>> choice would be to do Bluetooth PAN. This would require 'pand' and
>> modules on the Neo1973 side. The device should be configured as a
>> Bluetooth NAP, I guess.
> Hmm, I was thinking of putting the NAP on the other side, but it can
> make sense to do it this way too, one supposes. Anyways, once I get my
> Neo, I'll certainly be exploring Bluetooth PAN networking for wireless
> at home and perhaps work (and hey, then I can use my laptop as a BT/WiFi
> bridge ;P ).

Well, you seem to be mostly thinking about connecting the Neo1973 to
the internet via Bluetooth to get a better network connection than
GPRS - where as I am mostly thinking about getting other devices
connected to the internet via GPRS in places where no other network
connection is available. Access to the local network works both ways

> (I'll pass on DUN, it's just... more of a kludge, and we have a proper
> hackable system to be able to do it right. Some may of course find it
> useful for legacy device connectivity via Neo.)

I guess I will too. All the devices I am likely to use can be
configured to do PAN as well.

-- Naked

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