Attention is currently required from: pespin. dexter has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-pcu/+/31156 ) Change subject: pcuif_proto: rename PCU_IF_SAPI_AGCH_DT to PCU_IF_SAPI_PCH_DT ...................................................................... Patch Set 1: (2 comments) Commit Message: https://gerrit.osmocom.org/c/osmo-pcu/+/31156/comment/6763a1dc_68f5b3b2 PS1, Line 10: describes a method to send immediate assignment messages (normally AGCH) In the CS call world the immediate assignment is sent through the AGCH. But with GPRS it became necessary to send the immediate assignment through the PCH. (unfortunately it was never specified how to instruct this on RSL level, but thats also the reason why ericsson has those proprietary IEs in the assignment) The reason for this to be able to directly assign a downlink TBF to the MS. The MS essentially gets paged with all information it needs to go on the PDCH directly. For uplink TBFs things are normal again. The immediate assignment goes through the AGCH there. File include/osmocom/pcu/pcuif_proto.h: https://gerrit.osmocom.org/c/osmo-pcu/+/31156/comment/4809e556_55958d02 PS1, Line 42: #define PCU_IF_SAPI_PCH_DT 0x08 /* assignment on PCH (confirmed using TLLI) */ There are two ways to confirm an immediate assignment via PCH. From the PCU perspective you would either get an gsm_pcu_if_data or an gsm_pcu_if_data_cnf_dt, the latter one is the confirmation using the TLLI (directly). This is the method osmo-bsc is is using. The other method is that the other end sends the immediate assignment message back and then the TLLI is extracted from that message (see bts.cpp bts_rcv_imm_ass_cnf()). That is the method osmo-bts is using. Both ways to confirm the immediate assignment are valid and it does not matter if SAPI PCU_IF_SAPI_PCH_DT or PCU_IF_SAPI_PCH was used before. -- To view, visit https://gerrit.osmocom.org/c/osmo-pcu/+/31156 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-pcu Gerrit-Branch: master Gerrit-Change-Id: I6dfb8035134bc85a025415bd6c2f9c01987d9268 Gerrit-Change-Number: 31156 Gerrit-PatchSet: 1 Gerrit-Owner: dexter <pmaier(a)sysmocom.de> Gerrit-Reviewer: Jenkins Builder Gerrit-CC: pespin <pespin(a)sysmocom.de> Gerrit-Attention: pespin <pespin(a)sysmocom.de> Gerrit-Comment-Date: Fri, 03 Feb 2023 10:09:44 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: pespin <pespin(a)sysmocom.de> Gerrit-MessageType: comment