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E1 Reestablishment

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- PDCP reestablishment on CUCP (DRBs) triggering Bearer Context Modification procedures over E1
- Performing PDCP reestablishment for requested DRBs on CUUP
- Introduced function to notify re-establishment to CU-UP
- removed call to PDCP reestablishment for the DRBs on CUCP (it's done on CUUP)

cuup_notify_reestablishment:

- to fetch PDU session to setup in E1 following logic as in e1_send_bearer_updates
- fill bearer context modification request with stored F1-U tunnel information
  during E1 reestablishment, otherwise it would initialized to 0 by default
- update GTP tunnel with the stored configuration after E1 reestablishment
This commit is contained in:
Guido Casati
2024-03-01 09:48:35 +01:00
parent c83ff4c388
commit 2a078c757b
6 changed files with 94 additions and 27 deletions
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openair2/RRC/NR/rrc_gNB.c
+58 -10
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@@ -902,7 +902,60 @@ static pdu_session_to_mod_t *find_or_next_pdu_session(e1ap_bearer_mod_req_t *bea
return &bearer_modif->pduSessionMod[bearer_modif->numPDUSessionsMod - 1];
}
//-----------------------------------------------------------------------------
/**
* @brief Notify E1 re-establishment to CU-UP
*/
static void cuup_notify_reestablishment(gNB_RRC_INST *rrc, gNB_RRC_UE_t *ue_p)
{
e1ap_bearer_mod_req_t req = {
.gNB_cu_cp_ue_id = ue_p->rrc_ue_id,
.gNB_cu_up_ue_id = ue_p->rrc_ue_id,
};
if (!ue_associated_to_cuup(rrc, ue_p))
return;
/* loop through active DRBs */
for (int drb_id = 1; drb_id <= MAX_DRBS_PER_UE; drb_id++) {
if (ue_p->established_drbs[drb_id - 1].status == DRB_INACTIVE)
continue;
/* fetch an existing PDU session for this DRB */
rrc_pdu_session_param_t *pdu = find_pduSession_from_drbId(ue_p, drb_id);
if (pdu == NULL) {
LOG_E(RRC, "UE %d: E1 Bearer Context Modification: no PDU session for DRB ID %d\n", ue_p->rrc_ue_id, drb_id);
continue;
}
/* Get pointer to existing (or new one) PDU session to modify in E1 */
pdu_session_to_mod_t *pdu_e1 = find_or_next_pdu_session(&req, pdu->param.pdusession_id);
AssertError(pdu != NULL,
continue,
"UE %d: E1 Bearer Context Modification: PDU session %d to setup is null\n",
ue_p->rrc_ue_id,
pdu->param.pdusession_id);
/* Prepare PDU for E1 Bearear Context Modification Request */
pdu_e1->sessionId = pdu->param.pdusession_id;
/* Fill DRB to setup with ID, DL TL and DL TEID */
DRB_nGRAN_to_mod_t *drb_e1 = &pdu_e1->DRBnGRanModList[pdu_e1->numDRB2Modify];
drb_e1->id = drb_id;
drb_e1->numDlUpParam = 1;
drb_t *drbs = &ue_p->established_drbs[drb_id];
memcpy(&drb_e1->DlUpParamList[0].tlAddress, &drbs->f1u_tunnel_config.cuup_addr_f1u.buffer, sizeof(uint8_t) * 4);
drb_e1->DlUpParamList[0].teId = drbs->f1u_tunnel_config.cuup_teid_f1u;
/* PDCP configuration */
bearer_context_pdcp_config_t *pdcp_config = &drb_e1->pdcp_config;
drb_t *rrc_drb = get_drb(ue_p, drb_id);
set_bearer_context_pdcp_config(pdcp_config, rrc_drb, rrc->configuration.um_on_default_drb);
pdcp_config->pDCP_Reestablishment = true;
/* increase DRB to modify counter */
pdu_e1->numDRB2Modify += 1;
}
/* Send E1 Bearer Context Modification Request (3GPP TS 38.463) */
sctp_assoc_t assoc_id = get_existing_cuup_for_ue(rrc, ue_p);
rrc->cucp_cuup.bearer_context_mod(assoc_id, &req);
}
/**
* @brief RRCReestablishment message
* Direction: Network to UE
*/
static void rrc_gNB_generate_RRCReestablishment(rrc_gNB_ue_context_t *ue_context_pP,
const uint8_t *masterCellGroup_from_DU,
const rnti_t old_rnti,
@@ -941,17 +994,12 @@ static void rrc_gNB_generate_RRCReestablishment(rrc_gNB_ue_context_t *ue_context
for (int srb_id = 1; srb_id < NR_NUM_SRB; srb_id++) {
if (ue_p->Srb[srb_id].Active) {
nr_pdcp_config_set_security(ue_p->rrc_ue_id, srb_id, security_mode, kRRCenc, kRRCint, kUPenc);
// TODO: should send E1 UE Bearer Modification with PDCP Reestablishment flag
nr_pdcp_reestablishment(ue_p->rrc_ue_id, srb_id, true);
}
}
// TODO: should send E1 UE Bearer Modification with PDCP Reestablishment flag
for (int drb_id = 1; drb_id <= MAX_DRBS_PER_UE; drb_id++) {
if (ue_p->established_drbs[drb_id - 1].status != DRB_INACTIVE)
nr_pdcp_reestablishment(ue_p->rrc_ue_id, drb_id, false);
}
/* PDCP Reestablishment over E1 */
cuup_notify_reestablishment(rrc, ue_p);
/* F1AP DL RRC Message Transfer */
f1_ue_data_t ue_data = cu_get_f1_ue_data(ue_p->rrc_ue_id);
RETURN_IF_INVALID_ASSOC_ID(ue_data);
uint32_t old_gNB_DU_ue_id = old_rnti;
@@ -1788,7 +1836,7 @@ static void e1_send_bearer_updates(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, int n, f
LOG_E(RRC, "UE %d: UE Context Modif Response: no PDU session for DRB ID %ld\n", UE->rrc_ue_id, drb_f1->drb_id);
continue;
}
pdu_session_to_mod_t *pdu_e1 = find_or_next_pdu_session(&req, pdu_ue->param.pdusession_id);
pdu_session_to_setup_t *pdu_e1 = find_or_next_pdu_session(&req, pdu_ue->param.pdusession_id);
DevAssert(pdu_e1 != NULL);
pdu_e1->sessionId = pdu_ue->param.pdusession_id;
DRB_nGRAN_to_setup_t *drb_e1 = &pdu_e1->DRBnGRanModList[pdu_e1->numDRB2Modify];