Re: charset question (Greek)

>On Wed, Mar 13, 2002 at 10:22:40AM +0100, Andreas Fink wrote:
>>  I would suggest that recoding doesnt occur at all unless its necessary.
>>  This means that every SMSC driver would need to be aware of all
>>  coding types and recode once from source to target if needed.
>
>Unfortunately you can't do sms-split right without knowing the target
>character set.  Probably the smsbox will have to convert to the specified
>data coding (such as GSM charset) before splitting.  This might mean that
>the SMSC driver then has to convert back to iso-latin-1 or something in
>order to satisfy the SMSC protocol.
>
>A related problem is that the smsbox might not always know what the
>maximum sms size is.  Historically it is predictable, but it seems that
>for example SMPP is in the process of dropping these size limits.
>This might mean that the real solution is to push sms splitting all
>the way to the SMSC drivers, and provide library functions to avoid
>duplicated code.  But that means that the SMSC drivers would have to
>know about smsbox configurations such as split-chars and headers and
>footers...  It might simplify delivery notification, though, if an
>sms isn't split until the last moment.  On the other hand it might
>mean passing huge messages through the system because max-messages
>isn't applied until the last step.

I see. headers & footers is a problem in this.

Another way would be to carry the SMS always in binary format around. 
This means the format actually used on the over the air. This is more 
or less the binary version of the PDU format of the AT interface. In 
this case, the SMSC driver would simply do things like encoding the 
data in hex or so. For EMI it woudl split off the UDH, for AT it 
would work "as is" and for SMPP its pretty similar.  this would also 
work for HTTP interface for kannel-kannel (providing coding / charset 
are set correctly). Any SMSC types however who dont take binary 
format as input would be a problem then (some content gateway 
recently added could be a problem). If we cant code something in GSM 
binary format, we cant send it to a phone so its THE common format. 
However the question is also what happens to non GSM networks in this 
case. Are there any issues there maybe?

The advantage of this solution is that there is much less processing 
power needed in bearerbox and the cpu intensive tasks would be done 
in SMSBox which can be load shared easily. Also routing can work more 
efficiently as you would never have to think about recoding. The 
binary format is as close to GSM as it can be so every SMS protocol 
should be supportable.

Comments?

-- 

Andreas Fink
Fink-Consulting

------------------------------------------------------------------
Tel: +41-61-6932730 Fax: +41-61-6932729  Mobile: +41-79-2457333
Address: A. Fink, Schwarzwaldallee 16, 4058 Basel, Switzerland
E-Mail:  [email protected]  Homepage: http://www.finkconsulting.com
------------------------------------------------------------------
Something urgent? Try http://www.smsrelay.com/  Nickname afink