ONUs

An ONU (Optical Network Unit, also called ONT) is the fiber device at the subscriber's home. Zal Ultra finds the ONUs on each OLT and keeps their status and signal up to date.

Discover ONUs

Open the OLT (Network → OLTs → View) and click Discover ONUs. You can also click the Discover ONUs (search) icon in the OLT list.

Discovery runs in the background and shows its progress:

1. Discovering ONUs from OLT via SNMP...
2. Saving ONUs to database (x/y)...
3. Fetching signal metrics for N ONUs...

When it is done you see Discovery completed! N ONUs saved. with the number Discovered, Saved and Skipped. A large OLT can take a few minutes; you can leave the page and come back.

What discovery does:

• New ONUs are added.
• Known ONUs are updated. Their subscriber links are kept.
• ONUs that are no longer on the OLT are not removed. You can delete them by hand (see Delete an ONU).
• ONUs are not linked to subscribers automatically. Link them as described in Map ONUs to Subscribers.

Zal Ultra also runs discovery by itself every hour on every enabled, online OLT, so new ONUs appear without clicking anything.

ONU list

Go to Network → ONUs to see the ONUs of all OLTs, or open an OLT to see only its ONUs (ONUs on this OLT).

Column	Meaning
MAC Address	The ONU's MAC address, with the device maker under it. On Huawei OLTs this shows the ONU serial number. System Generated means the OLT did not report a MAC, so Zal Ultra made an ID from the ONU's position
OLT Name	The OLT the ONU is on (ONU list only)
Slot/Card	Frame/slot on the OLT, where the OLT reports it
PON : ONT	PON port and ONU number on that port
Status	See ONU status
Signal	Signal quality — see Signal quality
RX Power / TX Power	Optical power received and sent by the ONU, in dBm
Temp	ONU temperature in °C
Subscriber	The linked subscriber (click to open the profile), or Unmapped
Last Seen	The last time Zal Ultra read this ONU from the OLT

N/A means the OLT did not give that reading — normal for offline ONUs and for readings your model does not support.

Filters and search

On Network → ONUs:

• Filter by OLT — one OLT or all OLTs
• Status — Online, Offline, LOS or Dying Gasp
• Signal Status — Excellent, Good, Fair, Poor or Critical
• Mapping — Unmapped Only shows ONUs not yet linked to a subscriber

Click Apply to filter and Reset to clear. The search box finds ONUs by MAC address, serial number or interface. On an OLT's page the search also finds the subscriber's username or name.

Use Print, Copy, PDF, Excel or CSV to export the list, and View to choose the columns.

Find weak connections

Set Signal Status to Poor or Critical to list the ONUs that need attention, or Status to LOS to find cut fibers.

ONU status

Status	Meaning
Online	The ONU is connected and working
Offline	The ONU is not connected (for example powered off)
LOS	Loss of signal: the ONU gets no light — usually a cut or disconnected fiber
Dying_gasp	The ONU reported a power loss before going down — usually the subscriber's power is off
Unknown	The OLT did not report a status

Refresh the readings

Readings refresh automatically every 30 minutes. To get them now:

• All ONUs of an OLT — open the OLT and click Refresh Metrics above the ONU table, or on Network → ONUs choose the OLT in Filter by OLT and click Refresh Metrics. It runs in the background and shows Metrics updated successfully! with the number Updated and Failed.
• One ONU — click the Refresh Metrics icon on its row, or Refresh Metrics on its details page.

ONU details page

Click View Details (eye icon) on an ONU.

• ONU Details — MAC address, serial number, OLT, slot/card, PON port and ONT ID, full interface name, status, signal status, the linked subscriber and when it was last seen.
• Current Metrics — RX power, TX power, temperature, voltage, current and distance (meters from the OLT).
• Signal History — a chart of RX power, TX power and temperature. Choose Last 6 Hours, 12 Hours, 24 Hours, 48 Hours or 7 Days. A history point is saved each time the ONU's readings are refreshed.
• Recent Monitoring Logs — the readings of the last 24 hours in a table.

Use the history to see whether a weak signal is new (a recent fiber problem) or has always been low (a long or badly spliced fiber run).

Delete an ONU

On the ONU list or the OLT's ONU table, click Delete ONU (trash icon) and confirm. The ONU, its history and its subscriber link are removed.

If the ONU is still connected to the OLT, the next discovery adds it again, without a subscriber link.

Clear all ONUs

On the OLT's page, Clear All ONUs deletes every ONU of that OLT from Zal Ultra, with all their history, so you can discover them again from scratch — for example after replacing the OLT or when the list is out of date.

Subscriber links are lost

Clear All ONUs also removes the link between every ONU of the OLT and its subscriber. After discovering again, you have to map the ONUs to subscribers again. Use it only when you really need a fresh start.