configuration

Network Settings

Please note that nextepc.conf is used only if NextEPC is executed through nextepc-epcd. Otherwise, mme.conf, sgw.conf, pgw.conf, hss.conf, and pcrf.conf should be modifed for the configuration.


IP Connectivity between Network Entities

The minimum requirement of having IP connectvity is to modify the configuration files of MME and SGW.

  • Modification of MME config

    In /etc/nextepc/mme.conf, go to mme → s1ap. Please set your IP address after addr: keyword:
mme:
    freeDiameter: mme.conf
    s1ap:
      addr: <IP address>
...

  • Modification of SGW config

    In /etc/nextepc/sgw.conf, go to sgw → gtpu. Please set your IP address after addr: keyword.
sgw:
    gtpc:
      addr: 127.0.0.2
    gtpu:
      addr: <IP address>
...

Internet Access for UEs

First, please make sure that ip_forwarding = 1:

sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 0

sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"

Second, either method A or B is required for UEs to have Internet connectivity.

  • A. Adding a route on the gateway router

    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. The following example shows adding two routes for 45.45.0.0/16 and cafe::0/64 in Linux:
sudo ip route add 45.45.0.0/16 via <'PGW IP address'>
sudo ip route add cafe::0/64 via <'PGW IP address'>

  • B. NAT on PGW

    NAT can be done on NextEPC's PGW. You execute the following command in PGW installed host. Please check your outgoing network interface name (e.g enp0s25, wls3):
sudo iptables -t nat -A POSTROUTING -o <'interface-name'> -j MASQUERADE
sudo iptables -I INPUT -i pgwtun -j ACCEPT

Default Config

  • Network address settings

* MME
  S1AP: listen on all address avaiable in system
  GTP-C: listen on the first IP address in system
  DIAMETER: 127.0.0.2 (No TLS)

* SGW
  GTP-C: 127.0.0.2
  GTP-U: listen on the first IP address in system

* PGW
  GTP-C: Both 127.0.0.3 and [::1]
  GTP-U: Both 127.0.0.3 and [::1]
  DIAMETER: 127.0.0.3 (No TLS)

* HSS
  DIAMETER: 127.0.0.4 (No TLS)

* PCRF
  DIAMETER: 127.0.0.5 (No TLS)

  • UE IP addressing

* IPv4 : 45.45.0.1/16
* IPv6 : cafe::1/64

  • DNS setttings

* IPv4
  Primary : 8.8.8.8 
  Secondary : 8.8.4.4

* IPv6
  Primary : 2001:4860:4860::8888
  Secondary : 2001:4860:4860::8844