5G Core Lab - 50 Step Command Guide

Complete step-by-step commands to operate the Open5GS + UERANSIM lab environment

Lab Server Details

Server IP:	Provided in your lab access email
SSH User:	Provided in your lab access email
Web UI:	Check your lab access email for credentials
PLMN:	MCC: 999, MNC: 70
Test IMSI:	999700000000001

Quick Navigation

1-5 Server Access & Check 6-15 Service Management 16-25 Start gNB & UE 26-35 Connectivity Tests 36-42 View Logs 43-50 Traffic Capture & Debug

Section 1: Server Access & Initial Check (Steps 1-5)

Connect to Lab Server via SSH

Open terminal and connect to the 5G Core lab server

ssh username@your-server-ip

Check Server Information

Verify server hostname and OS version

hostname && cat /etc/os-release | head -3

Expected Output:

srv1098713 PRETTY_NAME="Ubuntu 24.04.1 LTS" NAME="Ubuntu" VERSION_ID="24.04"

Check System Resources

Verify available memory and CPU

free -h && nproc

Check Network Interfaces

View all network interfaces including ogstun

ip addr show | grep -E "^[0-9]+:|inet " | head -20

Check MongoDB Status

MongoDB stores subscriber data - ensure it's running

systemctl status mongod | head -5

Expected Output:

● mongod.service - MongoDB Database Server Loaded: loaded Active: active (running)

Section 2: Open5GS Service Management (Steps 6-15)

Check All Open5GS Services

View status of all 5G Core network functions

systemctl list-units --type=service | grep open5gs

Expected Output (All should be "running"):

open5gs-amfd.service loaded active running Open5GS AMF Daemon open5gs-ausfd.service loaded active running Open5GS AUSF Daemon open5gs-bsfd.service loaded active running Open5GS BSF Daemon open5gs-nrfd.service loaded active running Open5GS NRF Daemon open5gs-nssfd.service loaded active running Open5GS NSSF Daemon open5gs-pcfd.service loaded active running Open5GS PCF Daemon open5gs-scpd.service loaded active running Open5GS SCP Daemon open5gs-smfd.service loaded active running Open5GS SMF Daemon open5gs-udmd.service loaded active running Open5GS UDM Daemon open5gs-udrd.service loaded active running Open5GS UDR Daemon open5gs-upfd.service loaded active running Open5GS UPF Daemon

Check AMF Status (Access & Mobility)

AMF handles UE registration and mobility

systemctl status open5gs-amfd --no-pager | head -10

Check SMF Status (Session Management)

SMF manages PDU sessions

systemctl status open5gs-smfd --no-pager | head -10

Check UPF Status (User Plane)

UPF handles actual data traffic

systemctl status open5gs-upfd --no-pager | head -10

Check NRF Status (Network Repository)

NRF provides service discovery for all NFs

systemctl status open5gs-nrfd --no-pager | head -10

View AMF Configuration

Check PLMN and network settings in AMF

grep -A5 'plmn_id' /etc/open5gs/amf.yaml | head -10

Expected Output:

- plmn_id: mcc: 999 mnc: 70

View UPF Configuration

Check UE subnet pool configuration

grep -A3 'subnet' /etc/open5gs/upf.yaml

Expected Output:

session: - subnet: 10.45.0.0/16 gateway: 10.45.0.1

Restart All Open5GS Services

Use this if you need to restart the core network

systemctl restart open5gs-* && sleep 3 && systemctl status open5gs-amfd --no-pager | head -5

Check ogstun Interface (UPF Data Interface)

This interface handles UE data traffic

ip addr show ogstun

Expected Output:

ogstun: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> inet 10.45.0.1/16 scope global ogstun

Check Web UI Status

Web UI for subscriber management

systemctl status open5gs-webui --no-pager | head -5

Web UI Access: http://your-server-ip:9999
Username: (provided in your access email)
Password: (provided in your access email)

Section 3: Start gNB & UE (Steps 16-25)

Check Network Namespace

UE runs in isolated network namespace for proper routing

ip netns list

Expected Output:

ueransim

Check Namespace Network Connectivity

Verify namespace can reach the internet

ip netns exec ueransim ping -c 2 8.8.8.8

View gNB Configuration

Check gNB settings (PLMN, AMF address)

cat /opt/UERANSIM/config/ns-gnb.yaml

Expected Output:

mcc: '999' mnc: '70' nci: '0x000000010' tac: 1 linkIp: 192.168.100.1 ngapIp: 127.0.0.1 gtpIp: 127.0.0.1 amfConfigs: - address: 127.0.0.5 port: 38412

View UE Configuration

Check UE settings (IMSI, keys, APN)

cat /opt/UERANSIM/config/ns-ue.yaml | head -20

Expected Output:

supi: 'imsi-999700000000001' mcc: '999' mnc: '70' key: '465B5CE8B199B49FAA5F0A2EE238A6BC' op: 'E8ED289DEBA952E4283B54E88E6183CA' opType: 'OPC' gnbSearchList: - 192.168.100.1

Stop Any Running UERANSIM Processes

Clean up before starting fresh

pkill -9 nr-gnb 2>/dev/null; pkill -9 nr-ue 2>/dev/null; echo "Cleaned up"

Start gNB (5G Base Station)

Start gNB and connect to AMF

nr-gnb -c /opt/UERANSIM/config/ns-gnb.yaml > /tmp/gnb.log 2>&1 &

Verify gNB Connection

Check gNB connected to AMF successfully

sleep 3 && cat /tmp/gnb.log

Expected Output (Success):

UERANSIM v3.2.7 [sctp] [info] Trying to establish SCTP connection... (127.0.0.5:38412) [sctp] [info] SCTP connection established (127.0.0.5:38412) [ngap] [info] NG Setup procedure is successful

Start UE (User Equipment) in Namespace

Start UE inside network namespace

ip netns exec ueransim nr-ue -c /opt/UERANSIM/config/ns-ue.yaml > /tmp/ue.log 2>&1 &

Verify UE Registration

Check UE registered and PDU session established

sleep 5 && cat /tmp/ue.log

Expected Output (Success):

UERANSIM v3.2.7 [nas] [info] Selected plmn[999/70] [rrc] [info] RRC connection established [nas] [info] UE switches to state [MM-REGISTERED/NORMAL-SERVICE] [nas] [info] Initial Registration is successful [nas] [info] PDU Session establishment is successful PSI[1] [app] [info] Connection setup for PDU session[1] is successful, TUN interface[uesimtun0, 10.45.0.3] is up.

Check UE Status via CLI

Use nr-cli to check UE registration state

nr-cli imsi-999700000000001 -e status

Expected Output:

cm-state: CM-CONNECTED rm-state: RM-REGISTERED mm-state: MM-REGISTERED/NORMAL-SERVICE 5u-state: 5U1-UPDATED selected-plmn: 999/70

Section 4: Test Connectivity via 5G (Steps 26-35)

Check UE IP Address

View the IP address assigned to UE via 5G

ip netns exec ueransim ip addr show uesimtun0

Expected Output:

uesimtun0: <POINTOPOINT,UP,LOWER_UP> mtu 1400 inet 10.45.0.3/16 scope global uesimtun0

Check UE Routing Table

Verify default route via 5G tunnel

ip netns exec ueransim ip route show

Expected Output:

default dev uesimtun0 scope link 10.45.0.0/16 dev uesimtun0 proto kernel scope link src 10.45.0.3

Ping Test via 5G - Google DNS

Test ICMP connectivity through 5G network

ip netns exec ueransim ping -c 4 8.8.8.8

Expected Output:

PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=117 time=5.23 ms 64 bytes from 8.8.8.8: icmp_seq=2 ttl=117 time=4.15 ms --- 8.8.8.8 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss

Ping Test via 5G - Cloudflare DNS

Test connectivity to another DNS server

ip netns exec ueransim ping -c 4 1.1.1.1

DNS Resolution Test via 5G

Test DNS lookup through 5G network

ip netns exec ueransim nslookup google.com 8.8.8.8

Expected Output:

Server: 8.8.8.8 Address: 8.8.8.8#53 Non-authoritative answer: Name: google.com Address: 142.250.x.x

DNS Resolution - Your Domain

Test DNS lookup for cafetele.com

ip netns exec ueransim nslookup cafetele.com 8.8.8.8

TCP Connection Test via 5G

Test TCP connectivity to Google HTTPS

ip netns exec ueransim nc -zv 8.8.8.8 443 -w 5

Expected Output:

Connection to 8.8.8.8 443 port [tcp/https] succeeded!

HTTP Request via 5G

Test HTTP connectivity through 5G

ip netns exec ueransim curl -s -o /dev/null -w "%{http_code}" --connect-timeout 10 http://www.google.com

Expected Output:

200 or 301

Raw HTTP Request via 5G

Make raw HTTP request using netcat

ip netns exec ueransim bash -c 'echo -e "GET / HTTP/1.0\r\nHost: example.com\r\n\r\n" | nc -w 5 93.184.215.14 80 | head -10'

Expected Output:

HTTP/1.0 200 OK Content-Type: text/html; charset=UTF-8 ...

Check PDU Session Details

View active PDU sessions on UE

nr-cli imsi-999700000000001 -e ps-list

Expected Output:

PDU Session-1: state: PS-ACTIVE type: IPv4 apn: internet ip: 10.45.0.3

Section 5: View Logs (Steps 36-42)

View AMF Logs (UE Registration)

See UE registration, authentication events

journalctl -u open5gs-amfd -n 30 --no-pager

View AMF Logs in Real-time

Follow AMF logs live (Ctrl+C to stop)

journalctl -u open5gs-amfd -f

View SMF Logs (Session Management)

See PDU session creation events

journalctl -u open5gs-smfd -n 30 --no-pager

View UPF Logs (User Plane)

See data plane events

journalctl -u open5gs-upfd -n 30 --no-pager

View gNB Log

Check gNB connection and status

cat /tmp/gnb.log

View UE Log

Check UE registration and session status

cat /tmp/ue.log

View All Open5GS Logs

Check all NF log files

ls -la /var/log/open5gs/

Section 6: Traffic Capture & Debug (Steps 43-50)

Capture SCTP Traffic (N2 Control Plane)

Capture AMF-gNB signaling (Ctrl+C to stop)

tcpdump -i any sctp -c 20 -n

Capture GTP-U Traffic (User Plane)

Capture GTP tunneled traffic

tcpdump -i any port 2152 -c 20 -n

Capture Traffic on ogstun

See decapsulated UE traffic

tcpdump -i ogstun -c 20 -n

Save Capture to PCAP File

Save traffic for Wireshark analysis

tcpdump -i any sctp -c 50 -w /tmp/5g-capture.pcap && echo "Saved to /tmp/5g-capture.pcap"

View Subscriber in MongoDB

Check subscriber data in database

mongosh --quiet --eval 'db = db.getSiblingDB("open5gs"); db.subscribers.find({imsi:"999700000000001"}).pretty()' | head -30

Check NAT Rules

Verify NAT is configured for UE traffic

iptables -t nat -L POSTROUTING -v -n | grep 10.45

Expected Output:

MASQUERADE all -- * eth0 10.45.0.0/16 0.0.0.0/0

Deregister UE

Gracefully disconnect UE from network

nr-cli imsi-999700000000001 -e deregister normal

Stop All UERANSIM Processes

Clean shutdown of gNB and UE

pkill -9 nr-gnb; pkill -9 nr-ue; echo "UERANSIM stopped"

Quick Reference Card

Action	Command
SSH to server	`ssh username@your-server-ip`
Check all services	`systemctl status open5gs-*`
Start gNB	`nr-gnb -c /opt/UERANSIM/config/ns-gnb.yaml &`
Start UE	`ip netns exec ueransim nr-ue -c /opt/UERANSIM/config/ns-ue.yaml &`
Check UE status	`nr-cli imsi-999700000000001 -e status`
Ping via 5G	`ip netns exec ueransim ping 8.8.8.8`
View AMF logs	`journalctl -u open5gs-amfd -f`
Capture traffic	`tcpdump -i any sctp -n`
Stop UERANSIM	`pkill nr-gnb; pkill nr-ue`
Restart core	`systemctl restart open5gs-*`

Learning Resources

• Open5GS Documentation
• UERANSIM Wiki
• 3GPP Specifications