I can not capture the last UE ID that is generated by UERAMSIN during a simulation

General Discussions
#1

Currently, I am using two virtual machines (VM) to simulate UEs behaviour, the first VM has the control plane, and the second one has GNb/UERAMSIN. I am registering some UEs simultaneously using multiprocessing techniques in python and bash script (let’s say 20 UEs at the same time). Immediately when I trigger the registration of each UE, I need to capture the last UE ID that is generated by UERAMSIN during the simulation. Theoretically, these UE IDs are generated and assigned sequentially (1,2,3,4……) using ascending order. Therefore, I used the command “nr-cli UERANSIM-gnb-208-93-1 -e ue-list”, which displays the generated UEIDs in a descendent order, to read the first line of its output and save it in a txt file with the UE’s IMSI
The problem in this scenario using multiprocessing techniques to register several UEs simultaneously is that when I read the last UE ID generated by UERANSIM , I get the same value for all the UEs that are being registered. Consequently, I can not know or determine which will be the UE ID for each UE

Could you help me with this issue?

#2

Hi,
Could you provide python script and detailed set up?

#3

Hello JimmyMatrix.

Thanks for your help.

This is the python code:

from multiprocessing import Process

processes = []
UEs=[“ue100.yaml”,“ue101.yaml”,“ue102.yaml”,“ue103.yaml”,“ue104.yaml”,“ue105.yaml”,“ue106.yaml”,“ue107.yaml”,“ue108.yaml”,“ue109.yaml”]
for ue in UEs:
print("==========process number==============>",i,ue)
p = Process(target=run_command, args=([‘bash’, ‘./registration.sh’, ue],))
processes.append§
p.start()
time.sleep(1)

registration.sh is called from python: It is its code:

sudo $HOME/UERANSIM/build/nr-ue -c $HOME/UERANSIM/config/ue$1.yaml -n 1
textfile=“ueidlist.txt”
$HOME/UERANSIM/build/nr-cli UERANSIM-gnb-208-93-1 -e ue-list > $textfile

val=$(head -n 1 $textfile)

find="- ue-id: "

replace=""
ueid=${val//$find/$replace}
echo “imsi-208930000000$1,$ueid” >> ue$1.txt

and this is one example of a yaml file configuration. (it is the same for all UEs, the only difference with the rest one is the supi value)

IMSI number of the UE. IMSI = [MCC|MNC|MSISDN] (In total 15 digits)

supi: ‘imsi-208930000000100’

Mobile Country Code value of HPLMN

mcc: ‘208’

Mobile Network Code value of HPLMN (2 or 3 digits)

mnc: ‘93’

Permanent subscription key

key: ‘8baf473f2f8fd09487cccbd7097c6862’

Operator code (OP or OPC) of the UE

op: ‘8e27b6af0e692e750f32667a3b14605d’

This value specifies the OP type and it can be either ‘OP’ or ‘OPC’

opType: ‘OP’

Authentication Management Field (AMF) value

amf: ‘8000’

IMEI number of the device. It is used if no SUPI is provided

imei: ‘356938035643803’

IMEISV number of the device. It is used if no SUPI and IMEI is provided

imeiSv: ‘4370816125816151’

List of gNB IP addresses for Radio Link Simulation

gnbSearchList:

  • 129.192.83.238 #127.0.0.1

UAC Access Identities Configuration

uacAic:
mps: false
mcs: false

UAC Access Control Class

uacAcc:
normalClass: 0
class11: false
class12: false
class13: false
class14: false
class15: false

Initial PDU sessions to be established

sessions:

  • type: ‘IPv4’
    apn: ‘internet’
    slice:
    sst: 0x01
    sd: 0x010203

Configured NSSAI for this UE by HPLMN

configured-nssai:

  • sst: 0x01
    sd: 0x010203

Default Configured NSSAI for this UE

default-nssai:

  • sst: 1
    sd: 1

Supported integrity algorithms by this UE

integrity:
IA1: true
IA2: true
IA3: true

Supported encryption algorithms by this UE

ciphering:
EA1: true
EA2: true
EA3: true

Integrity protection maximum data rate for user plane

integrityMaxRate:
uplink: ‘full’
downlink: ‘full’

I do not have any problems to capture the last UE ID that is generated by UERAMSIN when I register each UE sequentially, the problem is when I use a multiprocessing technique to register several UEs at the same time.

#4

Hi,
following are my scripts
python:

from multiprocessing import Process
import time
import subprocess

i = 0
processes = []
UEs=['ue100.yaml', 'ue101.yaml', 'ue102.yaml', 'ue103.yaml', 'ue104.yaml','ue105.yaml','ue106.yaml','ue107.yaml', 'ue108.yaml', 'ue109.yaml' ]
for ue in UEs:
    print("==========process number==============>", i, ue)
    p = Process(target=subprocess.run, args=([["bash", "./registration.sh", ue],]))
    processes.append(p)
    p.start()
    time.sleep(1)
    i+=1

shell script:

sudo $HOME/UERANSIM/build/nr-ue -c $HOME/UERANSIM/config/$1 -n 1
textfile=“ueidlist.txt”
$HOME/UERANSIM/build/nr-cli UERANSIM-gnb-208-93-1 -e ue-list > $textfile

val=$(head -n 1 $textfile)

find="- ue-name: "

replace=""
ueid=${val//$find/$replace}

touch $1.txt

sudo chmod 777 $1.txt

echo “imsi-208930000000$1,$ueid” >> $1.txt

And according to shell script, it could happen race condition and synchronization problem:

$HOME/UERANSIM/build/nr-cli UERANSIM-gnb-208-93-1 -e ue-list > $textfile

val=$(head -n 1 $textfile)

If I/O halt the process or cost too many cpu time, system will context switch to another process. And when ctrl-c to interrupt the UERANSIM, the last ue id process would write ue-list to ueidlist.txt. Since there are 10 ue attaching to core network and executing in UERANSIM, the ue-list will output all ue id including the last one in the top of file, then remaining processes would perform val=$(head -n 1 $textfile), getting the last ue id.
Maybe more precise python and shell code for testing is required.

#5