Installing N3IWUE

In this demo we will practice:

Installing N3IWUE
Configuring free5GC and N3IWUE
Running N3IWUE to connect free5GC

1. Install N3IWUE VM

Repeat the steps of cloning free5gc VM from the base VM, create a new VM for the N3IWUE:

You can refer to Installing free5gc to install free5gc VM.
Name the VM N3IWUE, and create new MAC addresses for all network cards.
Make sure the VM has internet access and can log in using SSH.
Change the hostname to N3IWUE.
Make the Host-only network interface have static IP address 192.168.56.103.
Reboot the N3IWUE VM, as well as the free5gc VM.
You can ping 192.168.56.101 from the N3IWUE VM, and also ping 192.168.56.103 from the free5gc VM.

2. Install N3IWUE

To download N3IWUE in home directory:

cd ~
git clone https://github.com/free5gc/n3iwue.git
cd n3iwue

Update and upgrade the VM of N3IWUE:

sudo apt update
sudo apt upgrade

Install required tools:

sudo apt install make
sudo apt install libsctp-dev lksctp-tools
sudo apt install iproute2

Install Golang (use 1.21.6 version in this demonstrate):

wget https://dl.google.com/go/go1.21.6.linux-amd64.tar.gz
sudo tar -C /usr/local -zxvf go1.21.6.linux-amd64.tar.gz
mkdir -p ~/go/{bin,pkg,src}
echo 'export GOPATH=$HOME/go' >> ~/.bashrc
echo 'export GOROOT=/usr/local/go' >> ~/.bashrc
echo 'export PATH=$PATH:$GOPATH/bin:$GOROOT/bin' >> ~/.bashrc 
echo 'export GO111MODULE=auto' >> ~/.bashrc
source ~/.bashrc

# check your go installation
go version

Build N3IWUE

cd ~/n3iwue
make

3. Use WebConsole to Add UE

Open your web browser from your host machine, and enter the URL http://192.168.56.101:5000

On the login page, enter username admin and password free5gc.
Once logged in, widen the page until you see “Subscribers” on the left-hand side column.
Click on the Subscribers tab and then on the New Subscriber button
- Scroll down to Operator Code Type and change it from "OPc" to "OP".
- Make sure the following config between n3iwue/config/n3ue.yaml and Subscriber you create are the same:
  - PLMNID (ex. 208930000001234)
  - K
  - SQN
  - OP value (choose OP instead of OPC)
- Scroll all the way down and click on Submit.

4. Setting N3IWF Config

In free5gc VM, we need to edit N3IWF config file ~/free5gc/config/n3iwfcfg.yaml

Replace IKEBindAddress from 172.16.2.100 to 192.168.56.101, namely from:

  IKEBindAddress: 172.16.2.100 # Nwu interface  IP address (IKE) on this N3IWF

into:

  IKEBindAddress: 192.168.56.101 # Nwu interface  IP address (IKE) on this N3IWF

5. Setting N3IWUE

To let N3IWUE knows where is the N3IWF is, we need to edit the UE config file ~/n3iwue/config/n3ue.yaml in N3IWUE VM

Replace these parameters:

N3IWFInformation:
  IPSecIfaceAddr: 10.0.1.1 # IP address of Nwu interface (IKE) on N3IWF

N3UEInformation:
  IPSecIfaceName: ens38 # Name of Nwu interface (IKE) on this N3UE
  IPSecIfaceAddr: 10.0.1.4 # IP address of Nwu interface (IKE) on this N3UE

into:

N3IWFInformation:
  IPSecIfaceAddr: 192.168.56.101 # IP address of Nwu interface (IKE) on N3IWF

N3UEInformation:
  IPSecIfaceName: enp0s8 # Name of Nwu interface (IKE) on this N3UE (your interface name)
  IPSecIfaceAddr: 192.168.56.103 # IP address of Nwu interface (IKE) on this N3UE

6. Testing N3IWUE with free5GC

SSH into free5gc. If you have rebooted free5gc, remember to run:

sudo sysctl -w net.ipv4.ip_forward=1
sudo iptables -t nat -A POSTROUTING -o <dn_interface> -j MASQUERADE
# e.g. sudo iptables -t nat -A POSTROUTING -o enp0s3 -j MASQUERADE
sudo systemctl stop ufw
sudo systemctl disable ufw

Tip: Set net.ipv4.ip_forward=1 in /etc/sysctl.conf to enable packet forwarding permanently

In free5gc VM:

cd ~/free5gc
./run.sh -n3iwf

In N3IWUE VM:

cd ~/n3iwue
./run.sh

7. Result

Success: N3IWUE can ping data network through N3IWF