[PATCH 1/8] debug: Add DSS category for supplementary service

[sergey kostanbaev]

On Wed, Nov 25, 2015 at 4:12 PM, Holger Freyther <holger at freyther.de> wrote:

>
> > On 25 Nov 2015, at 14:07, sergey kostanbaev <sergey.kostanbaev at gmail.com>
> wrote:
> >
> > Yes, initially I thought about using SMPP for USSD. But it looked really
> complicated since only few external SMPP libraries have support of USSD and
> most of that few are in C#/Java/etc. Moreover I didn't have any working
> software for USSD over SMPP to test interoperability with.
>
> Hmm. We try to follow standard protocol when they exist. E.g. with "GSUP"
> the decision was
> that we have a good SS7 MAP stack (with high amount of tests and Q.787
> conformance) and
> doing that in C at the time didn't look like an economic choice.
>
> Do you remember how USSD is mapped to SMPP?
>
> Yeah I have a description but wasn't able to test it in a real
environment. I need to dig in my archives. I'll let you know.


>
>
> > So I decided to use GPRS SUP socket as a simple transport to send
> MAP-like messages. Workflow of this SUP is very simple and basically it
> forwards SS messages with little modifications.
>
> But why GPRS SUP then? E.g. it would be enough for you to use OAP (that
> just adds a very
> simple way for authentication)?  Which of the existing GSUP messages do
> you use?
>
> Well may be I wrongly used GPRS SUP as a description. I used none of GPRS
SUP messages.  I used the ability to send messages over "TCP" (TCP +
header) socket. Such code of a socket was in GSUP. I added
GPRS_GSUP_MSGT_USSD_MAP constant to not pollute and distinguish that
messages. It can b done on a raw socket, but I just reused GSUP socket
wrapper. May be this was confusing.


> holger
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