GSUP design questions

Harald Welte laforge at
Fri Apr 29 09:50:06 UTC 2016


I have some questions regarding GSUP design and current implementation
in ordre to help me undestand the rationale behind some of the

1) why are the fields like msisdn, vlr address, hlr address,, sgsn
   address still in their encoded form as part of struct
   osmo_gsup_message?  If there is a decoding/encoding function, why
   does it not go all the way?  Would anyone object if I was to change

2) osmo_gsup_message conatains multiple fields + associated length
   fields.  Wy not have a 'struct osmo_buflen { char *buf; size_t len }'
   which is re-used for all such fields that have buffer + length?  Then
   the respective code for dealing with such types could be generalized
   and shared.

3) why is the INSERT SUBSCRIBER DATA ignored by the SGSN, but rather it
   seems to expect the subscribe data piggy-backed onto the LOCATION
   UPDATE RESULT?  This seems to break the idea of staying as close as
   possible to the MAP level transactions while avoiding the
   encoding/decoding and underlying signalling protocol complexities.

Thanks in advance.

- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)

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