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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

Go to N3IWUE GitHub Repo.

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

Appendix