¶ Basic WiMAX Operations
Image nodes with the WiMAX client image, connect them to the WiMAX base station via wimaxcu, assign IP addresses, and verify node-to-node connectivity over the WiMAX interface.
¶ Overview
This tutorial walks through the basic steps required to run a WiMAX experiment on the COSMOS/ORBIT testbed. WiMAX (Worldwide Interoperability for Microwave Access) is a wireless broadband standard that routes all data traffic through a Base Station — similar to how a cell phone connects to a cell tower.
The experiment uses two sandbox nodes loaded with the WiMAX client image. After restoring the base station to its default settings, each node's WiMAX kernel module and daemon are confirmed to be running, the node connects to the WiMAX network using wimaxcu, and a static IP address is assigned to the WiMAX interface. Connectivity is then verified with ping between the two nodes over the WiMAX link.
The testbed base station is configurable, so the tutorial includes steps to reset it to known-good defaults before starting, avoiding configuration drift from previous experiments.
¶ Learning outcomes
After completing this tutorial you will be able to:
- Reset the WiMAX base station to default settings via HTTP commands.
- Load the WiMAX client disk image onto sandbox nodes with
omf load. - Verify that the
i2400m_usbWiMAX kernel driver andwimaxddaemon are running. - Connect a node to the WiMAX network with
wimaxcuand assign an IP address to thewmx0interface. - Test WiMAX connectivity between nodes using
ping.
¶ At a glance
| Difficulty | Beginner |
| Estimated time | 45 min |
| Domain / sandbox | sb4.cosmos-lab.org (Sandbox 4; has WiMAX base station and RF attenuator matrix) |
| Topic group | cellular-4g5g-oran |
| Last verified | Not re-tested (migrated 2026-06-20) |
¶ Prerequisites
Background knowledge
- Familiarity with SSH and basic Linux command-line usage.
- The COSMOS/ORBIT experiment basics — see the HelloWorld tutorial .
- Basic understanding of IP networking (addresses, subnets, ping).
Account & access
- A COSMOS account — register here.
- An approved reservation on sb4 (Sandbox 4) — see Make a reservation.
- SSH access to the domain console — see SSH access.
¶ Resources required
Devices / nodes
| Resource | Role | Qty | Notes |
|---|---|---|---|
| node1-4.sb4.cosmos-lab.org | WiMAX client node A | 1 | WiMAX USB dongle (i2400m_usb driver); IP 10.41.14.4 |
| node1-6.sb4.cosmos-lab.org | WiMAX client node B | 1 | WiMAX USB dongle (i2400m_usb driver); IP 10.41.14.6 |
Disk images
| Image | Load onto | Provides |
|---|---|---|
| wmx-tutorial.ndz | node1-4, node1-6 | WiMAX drivers (i2400m_usb), wimaxd daemon, wimaxcu utility |
Software components
| Component | Version | Source |
|---|---|---|
| i2400m_usb kernel module | TODO: verify | preinstalled in wmx-tutorial.ndz |
| wimaxd (WiMAX daemon) | TODO: verify | preinstalled in wmx-tutorial.ndz |
| wimaxcu (WiMAX Configuration Utility) | TODO: verify | preinstalled in wmx-tutorial.ndz |
| omf-5.3 | 5.3 | preinstalled on console |
Spectrum / RF / special
Sandbox 4 has a programmable WiMAX base station and a hardware RF attenuator matrix. The base station listens on wimaxrf:5052. This tutorial uses WiMAX network ID 51. The RF attenuator matrix state is left by previous experimenters and may require a manual reset if connectivity fails (see Troubleshooting).
¶ Topology
Sandbox 4 contains a WiMAX base station (wimaxrf) reachable at port 5052 from within the sandbox. Each experiment node connects to the base station over the air via a WiMAX USB dongle (interface wmx0). The base station bridges all node-to-node traffic, so node1-4 and node1-6 communicate through it rather than directly. The control plane (SSH, omf commands) uses the standard sandbox control network.
¶ Setup
-
Reserve Sandbox 4 and log into the console:
ssh <your_username>@console.sb4.cosmos-lab.org -
Restore the WiMAX base station to default settings:
wget -qO- http://wimaxrf:5052/wimaxrf/bs/default wget -qO- http://wimaxrf:5052/wimaxrf/bs/restartNote: After issuing the restart command the base station is unavailable for approximately 2 minutes. The following error during restart is normal — it means the base station has gone offline while rebooting:
Failed: 'Exception in snmp_set 'host 10.3.0.3 not responding''Note: For the outdoor testbed, use port 5054 instead:
wimaxrf:5054. -
Make sure the nodes are off before imaging:
omf-5.3 tell -a offh -t node1-4.sb4.cosmos-lab.org,node1-6.sb4.cosmos-lab.org -
Load the WiMAX client image onto both nodes (no spaces around commas):
omf-5.3 load -i wmx-tutorial.ndz -t node1-4.sb4.cosmos-lab.org,node1-6.sb4.cosmos-lab.orgThis process may take a few minutes.
-
Turn the nodes on:
omf-5.3 tell -a on -t node1-4.sb4.cosmos-lab.org,node1-6.sb4.cosmos-lab.org
¶ Instructions
¶ Step 1 — SSH into node1-4
ssh root@node1-4
If prompted to confirm the host key:
The authenticity of host 'node1-4 (10.14.1.4)' can't be established.
RSA key fingerprint is 62:ee:bf:75:50:84:f3:e8:86:f3:e5:e0:75:f0:3a:1a.
Are you sure you want to continue connecting (yes/no)?
Type yes and press Enter. After a successful login you will see:
root@node1-4:~#
¶ Step 2 — Verify WiMAX kernel driver
Check that the i2400m_usb driver is loaded:
lsmod
lsmod | grep i2400m_usb
If it is not listed, load it manually:
modprobe i2400m_usb
¶ Step 3 — Verify the WiMAX daemon
Call wimaxd to confirm another instance is already running (the daemon should start automatically when the modules load):
wimaxd
Expected output:
Enter Command:
q - Quit AppSrv
t - Trace ReInit (ReLoads Registry Values)
u - uplink(Apdo uplink event
h - Help
d - Toggle driver messages to display - debug & internal only
Another instance of wimax (pid 681) is already running!. Shutting down...
The last line confirms the daemon is running. If the daemon is not running, reload the kernel module (modprobe i2400m_usb) and retry.
¶ Step 4 — Connect to the WiMAX network
Use the WiMAX Configuration Utility to bring up the radio and connect to network 51:
wimaxcu ron
wimaxcu connect network 51
¶ Step 5 — Assign an IP address on node1-4
View the current interfaces, assign the WiMAX IP, and confirm:
ifconfig
ifconfig wmx0 10.41.14.4 netmask 255.255.0.0 up
ifconfig
The wmx0 interface should now show the assigned IP address.
IP address convention for sandbox nodes:
10.41.1X.Ywhere X = sandbox number, Y = node number (e.g., node1-4 on sb4 → 10.41.14.4).For the outdoor testbed:
10.41.40+X.Y
For the grid testbed:10.41.100+X.Ywhere X and Y are node coordinates.
¶ Step 6 — Repeat for node1-6
Open a second SSH session from the console and repeat Steps 1–5 for node1-6:
ssh root@node1-6
lsmod | grep i2400
modprobe i2400m_usb # only if needed
wimaxcu ron
wimaxcu connect network 51
ifconfig wmx0 10.41.14.6 netmask 255.255.0.0 up
¶ Step 7 — Test connectivity between nodes
From the node1-6 session, ping node1-4 over the WiMAX interface:
ping 10.41.14.4
Successful output looks like:
64 bytes from 10.41.14.4: icmp_seq=1 ttl=64 time=X.XX ms
...
¶ Verification
lsmod | grep i2400m_usbreturns at least one line on both nodes.wimaxdprints "Another instance of wimax ... is already running!" on both nodes.ifconfigon each node showswmx0with the assigned IP address (10.41.14.4 / 10.41.14.6).ping 10.41.14.4from node1-6 returns successful ICMP replies.
¶ Cleanup
omf-5.3 tell -a offh -t node1-4.sb4.cosmos-lab.org,node1-6.sb4.cosmos-lab.org
No omf save is needed unless you modified the image.
¶ Troubleshooting
| Symptom | Likely cause | Fix |
|---|---|---|
| SSH to a node fails with "No route to host" (see error below) | Node is off after imaging | Run omf-5.3 tell -a on -t node1-4.sb4.cosmos-lab.org; if still failing, cycle power with offh then on |
wimaxcu ron fails after modules are loaded |
wimaxd daemon not running |
Call wimaxd; if not running, reload the module (modprobe i2400m_usb) |
wimaxcu ron succeeds but ping fails |
Base station IP policy or RF attenuator issue | See the two checks below |
Base station restart error (snmp_set ... not responding) |
Normal during reboot | Wait 2 minutes and retry |
If SSH to a node returns an error like the following, the node is likely off after imaging:
ssh: connect to host node1-4.sb4.cosmos-lab.org port 22: No route to host
Checking and resetting base station client IP list:
A previous experimenter may have changed the allowed client IP list. Commands to inspect and modify it:
wget -qO- http://wimaxrf:5052/wimaxrf/datapath/clients/list
wget -qO- http://wimaxrf:5052/wimaxrf/datapath/clients/add...
wget -qO- http://wimaxrf:5052/wimaxrf/datapath/clients/delete...
Checking and resetting the RF Attenuator Matrix (Sandbox 4 only):
The hardware attenuator matrix may have been left at high attenuation by a previous user, blocking signals between nodes. Commands to inspect and reset attenuation between ports X and Y:
wget -qO- http://internal2dmz.orbit-lab.org:5052/instr/status
wget -qO- http://internal2dmz.orbit-lab.org:5052/instr/get?portA=X\&portB=Y
wget -qO- http://internal2dmz.orbit-lab.org:5052/instr/set?portA=X\&portB=Y\&att=0
¶ References
- COSMOS portal / account registration
- Make a reservation
- SSH access to consoles
- OMF commands reference
- WiMAX — Wikipedia
- HTTP GET methods
Author(s): COSMOS team · Last verified: Not re-tested (migrated 2026-06-20) · Tested image/release: wmx-tutorial.ndz / omf-5.3 · Tags: wimax, wimaxcu, wimaxd, i2400m, sandbox4, cellular