Alcatel band steering error
Alright Nurah, this one is a classic Alcatel / ALE Wi-Fi band-steering issue, and the log actually tells us exactly what’s happening π
Let’s break it down calmly and then I’ll guide you to fix it properly.
π What the log means (plain English)
Log message (key part):
[dcm] auth: Client 78:4b:87:e8:5f:82 tries to connect 2.4G radio,
the vap is ath001, disallowed by DCM,
Deny by 5Ghz Band Steering Enforcement Option.
Translation:
A client device (MAC:
78:4b:87:e8:5f:82)Is trying to connect to 2.4 GHz
On VAP ath001 (your SSID radio interface)
But DCM (Dynamic Client Management) says ❌ NO
Because Band Steering is forcing the client to use 5 GHz
So this is NOT an authentication failure, password issue, or encryption problem.
π It is intentional rejection by the controller.
π§ Why this happens
Band Steering is enabled, and ALE’s logic is:
“This client looks capable of 5 GHz → don’t let it sit on 2.4 GHz.”
This commonly happens when:
Device supports dual-band
RSSI is “good enough” for 5 GHz
5 GHz SSID is available
DCM policy = Enforce, not “Prefer”
⚠️ Why it becomes a problem in real life
Even though the device supports 5 GHz:
Some IoT devices
Older Android chipsets
Printers, scanners, industrial devices
π Try 2.4 GHz first and never retry 5 GHz properly
Result:
Endless connection attempts
ERR spam in logs
User says: “Wi-Fi can see but cannot connect”
✅ Quick checks you should do first
1️⃣ Confirm client capability
Check the device MAC 78:4b:87:e8:5f:82:
Is it:
Phone?
IoT?
Industrial panel?
Old laptop?
If it’s IoT / embedded / scanner / display board → π¨ red flag.
π ️ How to FIX it (best-practice options)
π’ Option 1 (Recommended): Set Band Steering to “Prefer 5 GHz”
Instead of Enforce
Why this works
Client is encouraged to use 5 GHz
But not blocked if it insists on 2.4 GHz
Where to change (ALE GUI):
Wireless → SSID / VAP Profile
→ Band Steering
→ Change from:
Enforce 5GHz
→ To:
Prefer 5GHz
✅ This solves 80% of real deployments
π‘ Option 2: Disable Band Steering for that SSID
Use this if:
SSID is meant for IoT / PA / PIDS / industrial devices
Stability > performance
Band Steering: Disabled
π Very common in railway & station systems (you’ll see this a lot in PIS/PA networks π)
π΅ Option 3: Separate SSIDs (Clean design)
Best for large systems:
| SSID | Band | Purpose |
|---|---|---|
STAFF-5G | 5 GHz only | Phones, laptops |
IOT-24G | 2.4 GHz only | PA, displays, controllers |
This avoids DCM fights entirely.
π΄ Option 4: Whitelist / Exempt client from DCM
If ALE version supports it:
Exclude MAC from band steering
Or lower steering aggressiveness
Use only when necessary (maintenance-heavy).
π§ͺ How to verify after fix
Clear logs
Reconnect the device
Check:
No more
[dcm] auth ERRClient associates successfully
RSSI stable
No roam loop
𧩠Extra tip (important for your railway projects)
For PIS / PA / display controllers / clocks:
❌ Avoid aggressive band steering
❌ Avoid “Enforce”
✅ Predictability > throughput
This exact issue shows up a lot in station deployments, especially with Android-based panels and embedded Wi-Fi modules.
Ulasan