gNB Simulator Deployment
gNB Simulator can be deployed in following modes,
gNB simulator in AIAB mode with 2 interfaces:
This is default mode of deployment for gNB Simulator
Multus cni needs to be enabled on cluster. Required for bess-upf & gNB
make 5gc will by default deploy gNB Simulator in this mode
One interface is used for user plane traffic towards UPF
Second interface is used to send traffic towards control plane (i.e. AMF).
UPF network & default gateway is provided in the override values.
Route to UPF network is added when POD comes up
defaultAs is configured per profile. This address is used to send data traffic during test
Note
Multiple gNB’s in one simulator instance need more changes in helm chart. This is pending work.
To add UPF routes. Following is example of override values
config:
gnbsim:
gnb:
ip: 192.168.251.5/24 #user plane IP at gnb if 2 separate interface provided
singleInterface: false
networkTopo:
- upfAddr: "192.168.252.3/32"
upfGw: "192.168.251.1"

gNB simulator running standalone with 2 or more interfaces
Install gNB Simulator on any K8s cluster
Multus cni needs to be enabled on cluster. Required for bess-upf & gNB
Make sure gNB Simulator can communicate with AMF & UPF
TODO - New Makefile target will deploy just 5G control plane
TODO - New Makefile target will deploy only gNB Simulator
One interface is used for user plane traffic towards UPF
Second interface is used to send traffic towards control plane (i.e. AMF).
UPF network & default gateway is provided in the override values.
Route to UPF network is added when POD comes up
defaultAs is configured per profile. This address is used to send data traffic during test
configure AMF address or FQDN appropriately
Note
Multiple gNB’s in one simulator instance need more changes in helm chart. This is pending work.
To add UPF routes. Following is example of override values
config:
gnbsim:
gnb:
ip: 192.168.251.5/24 #user plane IP at gnb if 2 separate interface provided
singleInterface: false
networkTopo:
- upfAddr: "192.168.252.3/32"
upfGw: "192.168.251.1"

gNB simulator running standalone with single interface
Install gNB Simulator on any K8s cluster
Multus cni needs to be enabled for the K8s cluster where bess-upf runs
Make sure gNB Simulator can communicate with AMF & UPF
TODO - New Makefile target will deploy just 5G control plane
TODO - New Makefile target will deploy only gNB Simulator
Single interface is used for user plane traffic towards UPF & as well traffic towards AMF
defaultAs is configured per profile. This address is used to send data traffic during test
configure AMF address or FQDN appropriately
Note
Multiple gNB’s can not be simulated since only 1 gNB will be able to use 2152 port
Following is example of override values
config:
gnbsim:
singleInterface: true
yamlCfgFiles:
gnb.conf:
configuration:
gnbs: # pool of gNodeBs
gnb1:
n3IpAddr: "POD_IP" # set if singleInterface is true

Description
The gNBSim tool simulates gNodeB and UE by generating and processing NAS and NGAP messages for the configured UEs and call flows. The tool currently supports simulation profiles for the following procedures,
Registration
UE Initiated PDU Session Establishment
UE Initiated De-registration.
AN Release
Ue Initiated Service Request Procedure
It is also capable to generate and send user data packets (ICMP echo request) and process down-link user data (ICMP echo response) over the established data plane path (N3 Tunnel).
Configure gNBSim
The config file for gNBSim can be found at <repo dir>/config/gnbsim.yaml
Note: The configuration has following major fields (Read the comments in the config file for more details)
- gnbs:
List of gNB’s to be simulated. Each item in the list holds configuration specific to a gNB.
- profiles:
List of test/simulation profiles. Each item in the list holds configuration specific to a profile.
Enable or disable a specific profile using the enable field.
Note: Currently following profiles are supported
- register:
Registration procedure
- pdusessest (Default):
Registration + UE initiated PDU Session Establishment + User Data packets
- deregister:
Registration + UE initiated PDU Session Establishment + User Data packets + Deregister
- anrelease:
Registration + UE initiated PDU Session Establishment + User Data packets + AN Release
- uetriggservicereq:
Registration + UE initiated PDU Session Establishment + User Data packets + AN Release + UE Initiated Service Request
Run gNBSim
To quickly launch and test AiaB with 5G SD-CORE using gNBSim:
$ make 5g-test
(refer AiaB documentation Aether In a Box)
- Alternatively, once 5G SD-CORE is up, you can enter into the gNBSim pod by
running:
$ kubectl exec -it gnbsim-0 -n omec bash
Then run following command to launch gNBSim:
$ ./gnbsim
Note: By default, the gNB Sim reads the configuration from /gnbsim/config/gnb.conf file. To provide a different configuration file, use the below command
$ ./gnbsim --cfg <config file path>
Build gNBSim
If you find a need to change gNBSim code and use the updated image in the AIAB setup then follow below steps.
To modify gNBSim and build a new docker image:
$ git clone https://github.com/omec-project/gnbsim.git $ cd gnbsim $ make docker-build #requires golang installed on the machine
To use newly created image in the AiaB cluster:
Update ~/aether-in-box/sd-core-5g-values.yaml to point to the newly built image, then run:
$ cd ~/aether-in-a-box/ $ make reset-5g-test
$ make 5g-test(refer AiaB documentation Aether In a Box)