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NR: fix: set PDCP discard timer to infinity

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The discard timer is used by the PDCP layer to discard packets that were not
transmitted to RLC after some time.

We don't really need it for the moment, maybe never for the default
bearer which is a best-effort bearer passing all kind of IP traffic.
Maybe for voice over IP kind of traffic it's important, or realtime
applications.

I ran an iperf UDP uplink test and saw no error on the PHY layer but still
lots of packets lost in the iperf logs, which was very surprising. By
analyzing the logs in wireshark I saw that, with the current scheduler,
an IP packet sent by the UE took 40ms to be sent piece by piece to the
gNB, and then the next uplink IP packet was never sent at all because
the discard timer was expired, leading to the high count of packets lost
in the iperf logs.

So let's put infinity for the moment for the discard timer. From my
understanding of the moment it's not a problem. If for some reason we
should set it to some non-infinity value, then we can change later.
This commit is contained in:
Cedric Roux
2021-03-10 10:30:23 +01:00
parent ea3f924632
commit 4ff8f8832e
3 changed files with 3 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
openair2/LAYER2/nr_pdcp/nr_pdcp_oai_api.c
+1 -1
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@@ -768,7 +768,7 @@ void nr_DRB_preconfiguration(uint16_t crnti)
drb_ToAddMod->pdcp_Config = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config));
drb_ToAddMod->pdcp_Config->drb = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb));
drb_ToAddMod->pdcp_Config->drb->discardTimer = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->discardTimer));
*drb_ToAddMod->pdcp_Config->drb->discardTimer=NR_PDCP_Config__drb__discardTimer_ms30;
*drb_ToAddMod->pdcp_Config->drb->discardTimer=NR_PDCP_Config__drb__discardTimer_infinity;
drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL));
*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL = NR_PDCP_Config__drb__pdcp_SN_SizeUL_len12bits;
drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeDL = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeDL));
openair2/RRC/NR/rrc_gNB.c
+1 -1
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@@ -631,7 +631,7 @@ rrc_gNB_generate_defaultRRCReconfiguration(
DRB_config->pdcp_Config = calloc(1, sizeof(*DRB_config->pdcp_Config));
DRB_config->pdcp_Config->drb = calloc(1,sizeof(*DRB_config->pdcp_Config->drb));
DRB_config->pdcp_Config->drb->discardTimer = calloc(1, sizeof(*DRB_config->pdcp_Config->drb->discardTimer));
*DRB_config->pdcp_Config->drb->discardTimer = NR_PDCP_Config__drb__discardTimer_ms30;
*DRB_config->pdcp_Config->drb->discardTimer = NR_PDCP_Config__drb__discardTimer_infinity;
DRB_config->pdcp_Config->drb->pdcp_SN_SizeUL = calloc(1, sizeof(*DRB_config->pdcp_Config->drb->pdcp_SN_SizeUL));
*DRB_config->pdcp_Config->drb->pdcp_SN_SizeUL = NR_PDCP_Config__drb__pdcp_SN_SizeUL_len18bits;
DRB_config->pdcp_Config->drb->pdcp_SN_SizeDL = calloc(1, sizeof(*DRB_config->pdcp_Config->drb->pdcp_SN_SizeDL));
openair2/RRC/NR/rrc_gNB_reconfig.c
+1 -1
View File
@@ -1347,7 +1347,7 @@ void fill_default_rbconfig(NR_RadioBearerConfig_t *rbconfig,
drb_ToAddMod->pdcp_Config = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config));
drb_ToAddMod->pdcp_Config->drb = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb));
drb_ToAddMod->pdcp_Config->drb->discardTimer = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->discardTimer));
*drb_ToAddMod->pdcp_Config->drb->discardTimer=NR_PDCP_Config__drb__discardTimer_ms30;
*drb_ToAddMod->pdcp_Config->drb->discardTimer=NR_PDCP_Config__drb__discardTimer_infinity;
drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL));
*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeUL = NR_PDCP_Config__drb__pdcp_SN_SizeUL_len18bits;
drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeDL = calloc(1,sizeof(*drb_ToAddMod->pdcp_Config->drb->pdcp_SN_SizeDL));