Wilfried,
Wilfried Mestdagh wrote:
Hi Andy,
What Angus do is an approach, but indeed as he claim, it can get a
expencieve, specially when the vehicles are in other countries.
You also have to be aware that another vehicle can connect with an IP
address of a 'loosed' vehicle, so then you have on your server 3
connections with same IP. Even worse, with most providers you can send
data to both of them without getting an error !! If you send data, then
the 'loose' one will disconnect... after... 5 minutes ... soemtime 30
minutes, depending on provider (most do it in 5 minutes). Even worse,
some providers do NAT, so then every vehicle has same IP address.
I see these problems also. I was told by the service provider that if
any data is transfered within a 3 minute period, the IP address will
remain the same. This is deffinately not the case. It's nice to know I'm
not on my own with this situation.
How I like this kind of problems :)
What I mostly do is design a protocol layer with a logon, and timed
keep-alive packets (witch cost money). I base on the logon where each
vehicle has his exclusive logon (eg the serial number of SIM card). When
a vehicle logs on, and it is already logged on, then the old one is
loose and I disconnect it.
I am currently using the IMEI to identify the vehicle. What I have tried
to do, but failed, is to identify the new connection, check for existing
connections and copy over the 'state' to the new connection, then drop
the old one. My failure so far is down to my 'delphi' skills, and not
ICS related.
Thanks for the input though.
...>Andy
---
Rgds, Wilfried
http://www.mestdagh.biz
Wednesday, June 29, 2005, 20:03, Info 2004 wrote:
Hi,
I have some vehicles with GPRS modems connected to O2 in the UK. The
problem I have is when the O2 "network" drops a connection to my server
- i.e. a close not initiated from the vehicle, or my server. When this
happens, I never see a disconnect, so the next time the unit reports in,
it usually has a different IP address, and I still have the previous
connection open, so I get a bit confused.
Does anyone else see the same issue? If so, how did you get around it?
I have based my server on SrvDemo.
All help appreciated.
Rgds...
..>>Andy
--
ASA Micros Ltd.
141 Wardle Road,
Wardle,
Rochdale.
OL12 9JA
UK
Tel: +44(0)1706 355057
Company No. 4722262
VAT No. 704044772
--
ASA Micros Ltd.
141 Wardle Road,
Wardle,
Rochdale.
OL12 9JA
UK
Tel: +44(0)1706 355057
Company No. 4722262
VAT No. 704044772
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