Does srsRAN E2 KPM expose PDCP volume (DRB.PdcpSduVolumeDL/UL) from CU-UP via FlexRIC?

[alektoja]

Hi all,

Issue
KPM subscription for PDCP volume on CU-UP is accepted, but no Indication messages arrive. DU metrics flow fine. With PDCP requested, I also see repeated “Resending Setup Request after timeout”.

Setup:
srsRAN - latest commit
FlexRIC
RIC: 127.0.0.1:36421/36422
gNB e2 config:

enable_du_e2: true
enable_cu_cp_e2: true
enable_cu_up_e2: true
e2sm_kpm_enabled: true
e2sm_rc_enabled: false

RIC sees 3 E2 nodes: ngran_gNB, ngran_gNB_CUUP, ngran_gNB_DU:

xApp subscriptions:
DU (works): DRB.UEThpDl, DRB.UEThpUl, RRU.PrbTotDl, RRU.PrbTotUl, DRB.RlcSduDelayDl (format=1).

CU-UP (problem):
Sub_ORAN_SM_List = (
{ name="KPM", time=1000, format=1, ran_type="ngran_gNB_CUUP",
actions=( {name="DRB.PdcpSduVolumeDL"}, {name="DRB.PdcpSduVolumeUL"} )
}
)
Also tried format=4 and ran_type=ngran_gNB - same results.

Logs:
RIC: multiple E2 SETUP-REQUEST rx for gNB / CUUP / DU; on PDCP sub sometimes Pending event timeout happened:
[iApp]: SUBSCRIPTION-REQUEST RAN_FUNC_ID 2 RIC_REQ_ID 1 tx
[iApp]: E42 SETUP-REQUEST rx
[iApp]: E42 SETUP-RESPONSE tx
[iApp]: E42 SETUP-REQUEST rx
[iApp]: E42 SETUP-RESPONSE tx
[iApp]: E42 SETUP-REQUEST rx
[iApp]: E42 SETUP-RESPONSE tx
[iApp]: E42 SETUP-REQUEST rx
[iApp]: E42 SETUP-RESPONSE tx
[iApp]: E42 SETUP-REQUEST rx

xApp: Successfully subscribed … then repeated E2AP: Resending Setup Request after timeout:
Setting the config -c file to /home/adun/xapp.conf
[LibConf]: loading service models from SM_DIR: /usr/local/lib/flexric/
[LibConf]: reading configuration for xApp
[LibConf]: NearRT_RIC IP: 127.0.0.1
[LibConf]: E42_Port Port: 36422
[LibConf]: Sub_ORAN_SM Name: KPM, Time: 1000
[LibConf]: format 4, RAN type ngran_gNB, actions = DRB.PdcpSduVolumeDL DRB.PdcpSduVolumeUL
[LibConf]: xApp_DB enable: 0
[xAap]: Initializing ...
[xApp]: nearRT-RIC IP Address = 127.0.0.1, PORT = 36422
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libpdcp_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/librc_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libgtp_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libkpm_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libslice_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libtc_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libmac_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/librlc_sm.so
[NEAR-RIC]: Loading SM ID = 144 with def = PDCP_STATS_V0
[NEAR-RIC]: Loading SM ID = 3 with def = ORAN-E2SM-RC
[NEAR-RIC]: Loading SM ID = 148 with def = GTP_STATS_V0
[NEAR-RIC]: Loading SM ID = 2 with def = ORAN-E2SM-KPM
[NEAR-RIC]: Loading SM ID = 145 with def = SLICE_STATS_V0
[NEAR-RIC]: Loading SM ID = 146 with def = TC_STATS_V0
[NEAR-RIC]: Loading SM ID = 142 with def = MAC_STATS_V0
[NEAR-RIC]: Loading SM ID = 143 with def = RLC_STATS_V0
[xApp]: DB_ENABLE = FALSE
[xApp]: do not initial database
[xApp]: E42 SETUP-REQUEST tx
[xApp]: E42 SETUP-RESPONSE rx
[xApp]: xApp ID = 19
[xApp]: Registered E2 Nodes = 3
Connected E2 nodes = 3
Registered node 0 ran func id = 2
[xApp]: reporting period = 1000 [ms]
Registered node 1 ran func id = 2
[xApp]: reporting period = 1000 [ms]
Registered node 2 ran func id = 2
[xApp]: reporting period = 1000 [ms]
xApp subscribes RAN Func ID 2 in E2 node idx 2, nb_id 411
E42_RIC_SUBSCRIPTION_REQUEST 31
[xApp]: E42 RIC SUBSCRIPTION REQUEST tx RAN_FUNC_ID 2 RIC_REQ_ID 1
[E2AP]: Resending Setup Request after timeout
[xApp]: Successfully subscribed to RAN_FUNC_ID 2
xApp running. Press CTRL+C to stop.
[E2AP]: Resending Setup Request after timeout
[E2AP]: Resending Setup Request after timeout

gNB:
E2AP: Connection to Near-RT-RIC on 127.0.0.1:36421 completed
E2AP: Connection to Near-RT-RIC on 127.0.0.1:36421 completed
E2AP: Connection to Near-RT-RIC on 127.0.0.1:36421 completed

Is DRB.PdcpSduVolumeDL/UL currently supported by srsRAN’s KPM on CU-UP? Any known issues with KPM v3 (format 1/4) for PDCP on CU-UP or with ran_type="ngran_gNB_CUUP"?

[pgawlowicz]

You have to enable reporting of proper metrics in gnb config file:

metrics:
  layers: 
    enable_pdcp: true                    # Optional BOOLEAN (false). Enable PDCP metrics
    enable_sched: true                    # Optional BOOLEAN (true). Enable DU scheduler metrics
    enable_rlc: true                     # Optional BOOLEAN (false). Enable RLC metrics
    enable_mac: true                     # Optional BOOLEAN (false). Enable MAC metrics
  periodicity: 
    cu_cp_report_period: 1000             # Optional UINT (1000). CU-CP metrics report period in milliseconds
    cu_up_report_period: 1000             # Optional UINT (1000). CU-UP metrics report period in milliseconds
    du_report_period: 1000                # Optional UINT:INT (1000). DU statistics report period in milliseconds. Format: [0 - 10485760].

[alektoja]

@pgawlowicz I already had a few of them added:
metrics:
layers:
enable_rlc: true # Enable RLC metrics
enable_sched: true # Enable DU scheduler metrics
enable_mac: true
enable_pdcp: true
periodicity:
du_report_period: 1000

I added the rest, and this is what it looks like now:
metrics:
layers:
enable_rlc: true # Enable RLC metrics
enable_sched: true # Enable DU scheduler metrics
enable_mac: true
enable_pdcp: true
periodicity:
du_report_period: 1000
cu_cp_report_period: 1000
cu_up_report_period: 1000

However, the result is the same:
[LibConf]: format 4, RAN type ngran_gNB_DU, actions = DRB.PdcpSduVolumeDL DRB.PdcpSduVolumeUL
[LibConf]: xApp_DB enable: 0
[xAap]: Initializing ...
[xApp]: nearRT-RIC IP Address = 127.0.0.1, PORT = 36422
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libpdcp_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/librc_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libgtp_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libkpm_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libslice_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libtc_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/libmac_sm.so
[E2-AGENT]: Opening plugin from path = /usr/local/lib/flexric/librlc_sm.so
[NEAR-RIC]: Loading SM ID = 144 with def = PDCP_STATS_V0
[NEAR-RIC]: Loading SM ID = 3 with def = ORAN-E2SM-RC
[NEAR-RIC]: Loading SM ID = 148 with def = GTP_STATS_V0
[NEAR-RIC]: Loading SM ID = 2 with def = ORAN-E2SM-KPM
[NEAR-RIC]: Loading SM ID = 145 with def = SLICE_STATS_V0
[NEAR-RIC]: Loading SM ID = 146 with def = TC_STATS_V0
[NEAR-RIC]: Loading SM ID = 142 with def = MAC_STATS_V0
[NEAR-RIC]: Loading SM ID = 143 with def = RLC_STATS_V0
[xApp]: DB_ENABLE = FALSE
[xApp]: do not initial database
[xApp]: E42 SETUP-REQUEST tx
[xApp]: E42 SETUP-RESPONSE rx
[xApp]: xApp ID = 7
[xApp]: Registered E2 Nodes = 3
Connected E2 nodes = 3
Registered node 0 ran func id = 2
Registered node 0 ran func id = 3
[xApp]: reporting period = 1000 [ms]
Registered node 1 ran func id = 2
Registered node 1 ran func id = 3
[xApp]: reporting period = 1000 [ms]
xApp subscribes RAN Func ID 2 in E2 node idx 1, nb_id 411
E42_RIC_SUBSCRIPTION_REQUEST 31
[xApp]: E42 RIC SUBSCRIPTION REQUEST tx RAN_FUNC_ID 2 RIC_REQ_ID 1
[E2AP]: Resending Setup Request after timeout
[xApp]: Successfully subscribed to RAN_FUNC_ID 2
Registered node 2 ran func id = 2
Registered node 2 ran func id = 3
[xApp]: reporting period = 1000 [ms]
xApp running. Press CTRL+C to stop.
[E2AP]: Resending Setup Request after timeout
[E2AP]: Resending Setup Request after timeout
[E2AP]: Resending Setup Request after timeout

[pgawlowicz]

could you share your configs and log files? also gnb_e2ap.pcap file?

[alektoja]

Following another thread, I switched to ORAN-SC-RIC and now it works.