Cellular Failover Not Ready (Mobile IP = 0.0.0.0)
Environment:
ISP Router → Pronto Router (PC61) → Cellular LTE Failover
Purpose
This document provides a structured troubleshooting and resolution procedure for incidents where the Cellular LTE uplink is not ready for failover because the mobile interface does not obtain an IP address.
This scenario typically occurs in dual WAN deployments where:
Primary WAN is wired broadband
Secondary WAN is LTE / 4G cellular
Automatic failover is configured on the Pronto Router (PC61)
A failover issue occurs when the cellular modem is unable to obtain an IP address from the carrier network, resulting in the interface showing:
Mobile IP = 0.0.0.0
In this state, LTE failover cannot activate, even though the wired WAN connection is working normally.
Scope
This SOP applies to:
Pronto Router (PC61) with LTE module
Cellular SIM based failover deployments
Wired WAN + LTE backup environments
Retail and restaurant locations requiring high availability internet
Assumptions
Wired WAN connection is operational
Cellular failover is configured
LTE SIM card is installed and Active with Data
Router is capable of LTE failover
Background – LTE Failover in Pronto Architecture
In a typical Pronto dual-WAN deployment:
The router maintains two WAN interfaces:
Interface | Role |
Wired WAN | Primary internet connection |
LTE / Cellular | Backup failover connection |
Even when the wired WAN is active, the LTE modem should remain attached to the carrier network and maintain a standby state.
Normal Operation
Condition | Expected Behavior |
Wired WAN Active | LTE modem attaches to cellular network |
LTE Registered | Cellular interface receives a valid IP address |
WAN Failure | Traffic automatically switches to LTE |
Wired Restored | Router automatically switches back to wired WAN |
If the LTE interface shows:
Mobile IP = 0.0.0.0
This means the modem has not successfully registered with the carrier network, and the failover path is not ready.
Problem Description
A cellular failover readiness issue occurs when:
Cellular modem shows Mobile IP = 0.0.0.0
Router cannot establish cellular data session
LTE failover remains inactive
Typical Symptoms
Operational Indicators
Wired WAN working normally
Router appears online in Pronto controller
LTE interface shows not ready / failed
Technical Indicators
Mobile IP address shows:
0.0.0.0
Cellular status may show Connected but no IP or status as failed
LTE failover does not activate during WAN outage
Typical Symptoms
Staff Reports
Internet works normally until wired connection fails
When primary WAN fails, site goes completely offline
LTE backup never activates
Technical Indicators
LTE status shows Connected but no IP
Cellular IP displayed as 0.0.0.0
Failover readiness state shows Not Ready
Business Impact
If LTE Failover Is Not Ready
Network has no redundancy
WAN outage causes complete site downtime
Operational Risks
POS transactions fail
Online ordering stops
Cloud services become unreachable
Payment terminals fail
Common Root Causes in Pronto Environments
SIM card inactive or suspended
Incorrect APN configuration
Cellular modem stuck during initialization
Weak LTE signal strength
LTE antennas disconnected or lose
Conjunction over selected LTE band
Carrier network failing to assign IP address
Detailed Troubleshooting Procedure
Step 1 — Immediate Reboot Validation (Mandatory)
If Mobile IP shows 0.0.0.0, first perform a router reboot.
Action
Reboot the router
Allow modem 3–5 minutes to initialize
Verify After Reboot,
Check the following parameters
SIM status
LTE signal strength
Signal quality
Expected Result
LTE interface should obtain a valid IP address from the carrier network.
If the IP address still shows 0.0.0.0, proceed to hardware checks.
Step 2 — Physical Hardware Verification
Inspect cellular hardware components.
Verify the Following
Both LTE antennas firmly connected
Antenna is not damaged
SIM card properly inserted
SIM card orientation correct
Additional Step
Remove and reseat SIM card
Power cycle router after reseating
Common Field Issue
In many deployments:
LTE antennas are not connected properly
Result:
Modem detects carrier signal
But IP assignment fails due to weak RF communication
Step 3 — LTE Band Configuration Validation
Action
Ensure device is not configured to a noise LTE band.
LTE signal strength: Select the appropriate available bands in area device is located by looking into carrier coverage portal using location address
Recommended to change LTE band based on availability and coverage
B2
B4
B12
Step 4 — SIM Status Verification
Verify SIM status using the carrier management portal.
Confirm the Following
SIM is active
SIM is not suspended
Data plan is valid
No billing restrictions exist
APN configuration correct
What is APN?
APN (Access Point Name) identifies the data network used by the carrier.
Incorrect APN settings can prevent the modem from obtaining an IP address.
If Required
Perform the following:
Re-provision SIM through carrier portal
Update APN profile in PCC portal
Reinsert SIM after activation
Reboot Router
Step 5 — Signal Strength Assessment
Even if LTE status shows Connected, poor signal may prevent IP assignment.
Problems Caused by Weak Signal
Carrier refuses IP assignment
Cellular sessions unstable
Failover unreliable
Field Optimization Tips
Improve signal by:
Moving router closer to window
Avoiding metal racks
Elevating device
Avoiding electrical interference
Installing Signal Booster
Recommended Signal Strength
Target:
Signal Quality Chart
10 Resolution Scenarios
Scenario A — SIM Not Active
Activate SIM through carrier portal.
Scenario B — APN Misconfiguration
Update APN settings to correct carrier profile.
Scenario C — Antenna or Signal Issue
Reconnect antennas and improve signal placement.
Scenario D — LTE Band Restriction
Enable multiple LTE bands supported by the carrier.
11 Validation After Fix
Confirm the following:
LTE interface obtains a valid IP address
Mobile IP no longer shows 0.0.0.0
LTE interface status shows Ready / Standby
Router successfully switches to LTE during WAN failure
Internet connectivity is restored during failover
Monitor behaviour for 10–15 minutes.