Feature #4627

show the last seen cell ID in the VLR

Added by neels 6 months ago. Updated 4 months ago.

Target version:
Start date:
Due date:
% Done:


Spec Reference:


for VLR subscribers and even in an active call the cell ID displays as zero in 'show subscriber cache' and 'show connection'.

We receive the Cell Id in the Complete Layer 3 Information.
osmo-msc currently stores that in the record for that active connection (msc_a), but fails to propagate that information to the VLR entry (vlr_subscr);
in msc_a.c:

        case RAN_MSG_COMPL_L3:
                msc_a->via_cell = (struct osmo_cell_global_id){
                        .lai.plmn = msc_a_net(msc_a)->plmn,
                gsm0808_cell_id_to_cgi(&msc_a->via_cell, msg->compl_l3.cell_id);

So to also update the VLR entry for that subsciber we could add there

                vsub->cgi = msc_a->via_cell;

Investigate whether msc_a->via_cell is actually required -- this could be the case if the cell information needs storing before a vlr_subscr is associated with the msc_a. If there is no such code path, we might as well just remove msc_a->via_cell and use only vlr_subscr->cgi.

In msc_vty.c, only vsub->cgi seems to get printed. If we keep msc_a->via_cell, the active connection should maybe rather print msc_a->via_cell, here:

static void vty_dump_one_conn(struct vty *vty, const struct msub *msub,
                              int offset, uint8_t dump_flags)
        if (vsub) {
                MSC_VTY_DUMP(vty, offset, "LAC / cell ID: %u / %u%s",
                             vsub->cgi.lai.lac, vsub->cgi.cell_identity,

Related issues

Related to OsmoMSC - Feature #4632: update the cell id in the VLR when receiving BSSMAP HANDOVER PERFORMED from the BSCNew06/24/2020


#1 Updated by neels 6 months ago

#2 Updated by laforge 5 months ago

  • Assignee set to neels
  • Priority changed from Normal to High

#3 Updated by neels 5 months ago

  • Related to Feature #4632: update the cell id in the VLR when receiving BSSMAP HANDOVER PERFORMED from the BSC added

#4 Updated by neels 5 months ago

#5 Updated by neels 5 months ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 90

#6 Updated by neels 4 months ago

  • Status changed from In Progress to Resolved
  • % Done changed from 90 to 100

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