**Cool project,
Please forgive if this is a stupid question. Currently on my 4th day of learning mobile telecoms.**
In the configuration guide you state..
IP Connectivity between Network Entities
The minimum requirement of having IP connectvity is to modify the configuration files of MME and SGW. Once NextEPC has been installed, you can find YAML-format configuration files in /etc/nextepc/*.conf.
Note that /etc/nextepc/nextepc.conf is just a manual. If you use nextepc-epcd in a build environment, this configuration file could be used, but if you installed it with the package manager, modifying this configuration file has no effect.
Anyway, before setting up, please decide a network interface to run NextEPC, and then the IP address of the interface needs to be recorded in the configuration files.
Modification of MME config
Open /etc/nextepc/mme.conf file, and find an item in mme โ s1ap. Please set your IP address with putting addr: keyword.
mme:
freeDiameter: mme.conf
s1ap:
addr:
...
Save and exit.
Modification of SGW config
Open /etc/nextepc/sgw.conf file, and find an item in sgw โ gtpu. Please set your IP address with putting addr: keyword.
sgw:
gtpc:
addr: 127.0.0.2
gtpu:
addr:
...
Save and exit.
Adding a route for UE to have Internet connectivity
By default, a LTE UE will receive a IP address with the network address of 45.45.0.0/16. If you have a NAT router (e.g., wireless router, cable modem, etc), the LTE UE can reach Internet in uplink, but it cannot in downlink. It's because the NAT router has no idea on 45.45.0.0/16, so adding a route is required. Please refer to the user manual to know how to add a static route in your router.
Add a route of both 45.45.0.0/16 and cafe::0/64 to go the PGW IP address. For example, a command for Linux will be:
sudo ip route add 45.45.0.0/16 via
sudo ip route add cafe::0/64 via
If you have no NAT router, there is another option for you. iptables can solve the problem. You execute the following command in NextEPC installed host. The eth0 shown below is just an example. Do not miss out on modifying your interface name(e.g enp0s25, wls3).
sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -I INPUT -i pgwtun -j ACCEPT