Cots UE connected to the GNB, but there is no access to internet

[mohammadih]

I did all the instructions for setting up the COTS UE, and what recommended in this link
#1087
I need to mention that phone connects to GNB correctly.
and these are the log files:
multipath1@multipath1-OptiPlex-7090:/etc/open5gs$ tail -f /var/log/open5gs/amf.log
07/08 12:59:31.480: [gmm] INFO: [imsi-999700000128971] Registration complete (../src/amf/gmm-sm.c:2658)
07/08 12:59:31.480: [amf] INFO: [imsi-999700000128971] Configuration update command (../src/amf/nas-path.c:607)
07/08 12:59:31.480: [gmm] INFO: UTC [2025-07-08T17:59:31] Timezone[0]/DST[0] (../src/amf/gmm-build.c:551)
07/08 12:59:31.480: [gmm] INFO: LOCAL [2025-07-08T12:59:31] Timezone[-18000]/DST[1] (../src/amf/gmm-build.c:556)
07/08 12:59:31.544: [amf] INFO: [Added] Number of AMF-Sessions is now 1 (../src/amf/context.c:2806)
07/08 12:59:31.544: [gmm] INFO: UE SUPI[imsi-999700000128971] DNN[internet] S_NSSAI[SST:1 SD:0xffffff] smContextRef[NULL] smContextResourceURI[NULL] (../src/amf/gmm-handler.c:1374)
07/08 12:59:31.544: [amf] INFO: [32d0e776-5c1e-41f0-ae23-8f64e63c4019] Setup NF Instance [type:SMF] (../src/amf/context.c:2429)
07/08 12:59:31.544: [gmm] INFO: SMF Instance [32d0e776-5c1e-41f0-ae23-8f64e63c4019] (../src/amf/gmm-handler.c:1415)
07/08 12:59:31.547: [amf] INFO: Setup NF EndPoint(addr) [127.0.0.4:7777] (../src/amf/nsmf-handler.c:144)
07/08 12:59:31.606: [amf] INFO: [imsi-999700000128971:1:11][0:0:NULL] /nsmf-pdusession/v1/sm-contexts/{smContextRef}/modify (../src/amf/nsmf-handler.c:942)

multipath1@multipath1-OptiPlex-7090:/etc/open5gs$ tail -f /var/log/open5gs/upf.log
07/08 12:09:32.090: [upf] INFO: [Added] Number of UPF-Sessions is now 1 (../src/upf/context.c:209)
07/08 12:09:32.090: [gtp] INFO: gtp_connect() [127.0.0.4]:2152 (../lib/gtp/path.c:60)
07/08 12:09:32.090: [upf] INFO: UE F-SEID[UP:0xdfe CP:0xf11] APN[internet] PDN-Type[1] IPv4[10.45.0.2] IPv6[] (../src/upf/context.c:495)
07/08 12:09:32.146: [gtp] INFO: gtp_connect() [127.0.0.1]:2152 (../lib/gtp/path.c:60)
07/08 12:09:45.426: [upf] INFO: [Removed] Number of UPF-sessions is now 0 (../src/upf/context.c:253)
07/08 12:10:18.808: [upf] INFO: [Added] Number of UPF-Sessions is now 1 (../src/upf/context.c:209)
07/08 12:10:18.808: [upf] INFO: UE F-SEID[UP:0x3d3 CP:0x3b8] APN[internet] PDN-Type[1] IPv4[10.45.0.3] IPv6[] (../src/upf/context.c:495)
07/08 12:42:03.383: [upf] INFO: [Removed] Number of UPF-sessions is now 0 (../src/upf/context.c:253)
07/08 12:59:31.550: [upf] INFO: [Added] Number of UPF-Sessions is now 1 (../src/upf/context.c:209)
07/08 12:59:31.550: [upf] INFO: UE F-SEID[UP:0x5da CP:0x88e] APN[internet] PDN-Type[1] IPv4[10.45.0.4] IPv6[] (../src/upf/context.c:495)

multipath1@multipath1-OptiPlex-7090:/etc/open5gs$ ps aux | grep open5gs
open5gs 1043 0.0 0.0 138940 13764 ? Ssl 12:06 0:00 /usr/bin/open5gs-bsfd -c /etc/open5gs/bsf.yaml
open5gs 1049 0.0 0.0 132092 16852 ? Ssl 12:06 0:00 /usr/bin/open5gs-nrfd -c /etc/open5gs/nrf.yaml
open5gs 1056 0.0 0.0 132388 20444 ? Ssl 12:06 0:01 /usr/bin/open5gs-scpd -c /etc/open5gs/scp.yaml
open5gs 1058 0.0 0.0 134284 18360 ? Ssl 12:06 0:00 /usr/bin/open5gs-seppd -c /etc/open5gs/sepp1.yaml
open5gs 4835 0.0 0.0 1729108 57264 ? Ssl 12:08 0:00 /usr/bin/open5gs-amfd -c /etc/open5gs/amf.yaml
open5gs 4836 0.0 0.0 133336 14264 ? Ssl 12:08 0:00 /usr/bin/open5gs-ausfd -c /etc/open5gs/ausf.yaml
open5gs 4837 0.0 0.0 2773048 15820 ? Ssl 12:08 0:01 /usr/bin/open5gs-mmed -c /etc/open5gs/mme.yaml
open5gs 4838 0.0 0.0 131576 14028 ? Ssl 12:08 0:00 /usr/bin/open5gs-nssfd -c /etc/open5gs/nssf.yaml
open5gs 4839 0.0 0.0 346404 27252 ? Ssl 12:08 0:00 /usr/bin/open5gs-sgwcd -c /etc/open5gs/sgwc.yaml
open5gs 4840 0.0 0.0 334288 25528 ? Ssl 12:08 0:00 /usr/bin/open5gs-sgwud -c /etc/open5gs/sgwu.yaml
open5gs 4841 0.0 0.0 3198848 54268 ? Ssl 12:08 0:02 /usr/bin/open5gs-smfd -c /etc/open5gs/smf.yaml
open5gs 4842 0.0 0.0 140072 14912 ? Ssl 12:08 0:00 /usr/bin/open5gs-udmd -c /etc/open5gs/udm.yaml
open5gs 4843 0.0 0.0 367200 34424 ? Ssl 12:08 0:00 /usr/bin/open5gs-upfd -c /etc/open5gs/upf.yaml
open5gs 5024 0.0 0.0 2774124 21976 ? Ssl 12:08 0:01 /usr/bin/open5gs-hssd -c /etc/open5gs/hss.yaml
open5gs 5025 0.0 0.0 161980 22644 ? Ssl 12:08 0:00 /usr/bin/open5gs-pcfd -c /etc/open5gs/pcf.yaml
open5gs 5026 0.0 0.0 2784360 22032 ? Ssl 12:08 0:01 /usr/bin/open5gs-pcrfd -c /etc/open5gs/pcrf.yaml
open5gs 5027 0.0 0.0 142288 22176 ? Ssl 12:08 0:00 /usr/bin/open5gs-udrd -c /etc/open5gs/udr.yaml
multipa+ 6852 0.0 0.0 16984 1668 pts/1 S+ 13:01 0:00 tail -f /var/log/open5gs/amf.log
multipa+ 6861 0.0 0.0 16984 1832 pts/3 S+ 13:02 0:00 tail -f /var/log/open5gs/upf.log
multipa+ 6864 0.0 0.0 17812 2188 pts/2 S+ 13:03 0:00 grep --color=auto open5gs
and GNB config file:

This configuration file example shows how to configure the srsRAN Project gNB to connect to a COTS UE. As with the

associated tutorial, this config has been tested with a OnePlus 8T. A B210 USRP is used as the RF-frontend.

This config creates a TDD cell with 20 MHz bandwidth in band 78.

To run the srsRAN Project gNB with this config, use the following command:

sudo ./gnb -c gnb_b210_20MHz_oneplus_8t.yaml

cu_cp:
amf:
addr: 127.0.1.100 # The address or hostname of the AMF.
bind_addr: 127.0.0.1 # A local IP that the gNB binds to for traffic from the AMF.
supported_tracking_areas: # Configure the TA associated with the CU-CP
- tac: 7
plmn_list:
- plmn: "99970"
tai_slice_support_list:
- sst: 1

ru_sdr:
device_driver: uhd # The RF driver name.
device_args: type=b200,num_recv_frames=64,num_send_frames=64 # Optionally pass arguments to the selected RF driver.
clock: external # Specify the clock source used by the RF. NOTE: Set to internal if NOT using an external 10 MHz reference clock.
srate: 23.04 # RF sample rate might need to be adjusted according to selected bandwidth.
otw_format: sc12
tx_gain: 80 # Transmit gain of the RF might need to adjusted to the given situation.
rx_gain: 40 # Receive gain of the RF might need to adjusted to the given situation.

cell_cfg:
dl_arfcn: 518598 # ARFCN of the downlink carrier (center frequency).
band: 41 # The NR band.
channel_bandwidth_MHz: 20 # Bandwith in MHz. Number of PRBs will be automatically derived.
common_scs: 30 # Subcarrier spacing in kHz used for data.
plmn: "99970" # PLMN broadcasted by the gNB.
tac: 7 # Tracking area code (needs to match the core configuration).
pci: 1 # Physical cell ID.

pcap:
mac_enable: false # Set to true to enable MAC-layer PCAPs.
mac_filename: /tmp/gnb_mac.pcap # Path where the MAC PCAP is stored.
ngap_enable: false # Set to true to enable NGAP PCAPs.
ngap_filename: /tmp/gnb_ngap.pcap # Path where the NGAP PCAP is stored.

the amf file:
logger:
file:
path: /var/log/open5gs/amf.log

level: info # fatal|error|warn|info(default)|debug|trace

global:
max:
ue: 1024 # The number of UE can be increased depending on memory size.

peer: 64

amf:
sbi:
server:
- address: 127.0.0.5
port: 7777
client:

nrf:

- uri: http://127.0.0.10:7777

  scp:
    - uri: http://127.0.0.200:7777

ngap:
server:

- address: 127.0.0.5 # changed for the test

  - address: 127.0.1.100

metrics:
server:
- address: 127.0.0.5
port: 9090
guami:
- plmn_id:
mcc: 999
mnc: 70
amf_id:
region: 2
set: 1
tai:
- plmn_id:
mcc: 999
mnc: 70
tac: 7
plmn_support:
- plmn_id:
mcc: 999
mnc: 70
s_nssai:
- sst: 1
security:
integrity_order : [ NIA2, NIA1, NIA0 ]
ciphering_order : [ NEA0, NEA1, NEA2 ]
network_name:
full: Open5GS
short: Next
amf_name: open5gs-amf0
time:

t3502:

value: 720 # 12 minutes * 60 = 720 seconds

t3512:
  value: 540    # 9 minutes * 60 = 540 seconds

and upf file:
logger:
file:
path: /var/log/open5gs/upf.log

level: info # fatal|error|warn|info(default)|debug|trace

global:
max:
ue: 1024 # The number of UE can be increased depending on memory size.

peer: 64

upf:
pfcp:
server:
- address: 127.0.0.7
client:

smf: # UPF PFCP Client try to associate SMF PFCP Server

- address: 127.0.0.4

gtpu:
server:

- address: 127.0.0.7 # Changed for the test

  - address: 127.0.1.100

session:
- subnet: 10.45.0.0/16
gateway: 10.45.0.1
- subnet: 2001:db8:cafe::/48
gateway: 2001:db8:cafe::1
metrics:
server:
- address: 127.0.0.7
port: 9090

multipath1@multipath1-OptiPlex-7090:/etc/open5gs$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.28.28.1 0.0.0.0 UG 100 0 0 enp0s31f6
10.28.28.0 0.0.0.0 255.255.255.0 U 100 0 0 enp0s31f6
10.45.0.0 0.0.0.0 255.255.0.0 U 0 0 0 ogstun
10.45.0.0 0.0.0.0 255.255.0.0 U 0 0 0 ogstun

any suggestion how to fix the issue?

[brendan-mcauliffe]

Hi @mohammadih,

Firstly, for future posts, please check the formatting, as it is quite hard to read through your issue in its current state.

Have you double-checked that the APN names are consistent across both the UE and the subscriber details in the core? If you have enabled IP forwarding correctly, I would look here to make sure everything is the same across both entries.

What is the status of the RF connection between the UE and the gNB? Are you seeing and Lates or other events?

Please provide some more details.