On 2/6/19 12:52 AM, Neels Hofmeyr wrote:
Now you know all the facts that I know, I'm currently not certain what would be the best to do. Can you figure it out?
After looking into the Wireshark dissector code, I came to the conclusion that the ISDN-AddressString is exactly what you are seeing in the dump. Furthermore, it is the same as the MSISDN.
Then I've looked up the existing MSISDN IE in the GSUP spec [1]:
ISDN-AddressString / MSISDN / Called Party BCD Number
The MSISDN is encoded as an ISDN-AddressString in 3GPP TS 09.02 and Called Party BCD Number in 3GPP TS 04.08. It will be stored by the SGSN or VLR and then passed as is to the GGSN during the activation of the primary PDP Context.
(It also has a graph that looks like what you see in Wireshark.)
So my conclusion is, that we can just drop the handover_number IE and use the existing msisdn_enc IE instead.
Regards, Oliver
[1]: https://git.osmocom.org/osmo-gsm-manuals/tree/common/chapters/gsup.adoc?id=6...