Device Roaming Issues Due to Poor Channel Plan or AP Placement
Purpose
This document provides a structured troubleshooting and resolution procedure for issues where wireless devices experience connectivity interruptions while roaming between access points.
In restaurant and retail environments, staff often move with handheld POS devices between areas such as:
Dining area
Kitchen
Counter
Storage rooms
During this movement, the client device should seamlessly roam from one AP to another.
If roaming is not optimized, devices may:
Disconnect during AP transition
Experience packet loss
Fail payment transactions
Delay order processing
Scope
This SOP applies to:
Pronto PC26 Access Points
Wireless POS handheld devices
Multi-AP wireless deployments
Sites experiencing disconnects while moving between AP coverage areas
This SOP does not apply to wired connectivity failures or WAN outages.
Environment
Typical Pronto wireless deployment:
PC61 router acting as gateway
Managed switch distributing VLANs
Multiple PC26 access points
POS SSID mapped to a dedicated VLAN
Wireless clients roaming between APs
Example architecture:
Problem Description
Wireless roaming occurs when a device moves from the coverage area of one AP to another AP.
Example:
POS device connected to AP1
Staff walks toward kitchen
Signal from AP1 weakens
Device should switch to AP2
If roaming behavior is not optimized, the device may:
Hold connection to AP1 too long
Disconnect before connecting to AP2
Experience packet loss during reassociation
This results in temporary connectivity loss during movement.
What Happens During Roaming Failure
When roaming does not occur correctly:
Signal strength gradually weakens
Device delays switching to a stronger AP
Reassociation time increases
Wireless packets are dropped
Possible outcomes include:
POS payment session timeout
Application disconnection
Temporary Wi-Fi reconnection
Typical Symptoms
Staff may report:
POS disconnects when walking between areas
Payment terminals fail when moving
Wi-Fi reconnect messages appear during movement
Transactions fail while staff walk through restaurant
Technical indicators include:
Clients staying connected to distant APs
Weak RSSI values
Increased wireless retries
Roaming events observed in controller logs
Common Root Causes in Pronto Deployments
Access points placed too far apart
AP transmit power set too high
Adjacent APs using the same channel
Improper channel planning
Lack of overlapping coverage areas
Interference from kitchen equipment
Physical obstructions such as walls or metal structures
Wrong dbm value configured in Roam SNR
Association Steering is enabled in Radio Profile
Technical Explanation
Wi-Fi roaming is client-driven, meaning the device decides when to switch APs.
The client monitors:
Signal strength (RSSI)
Signal quality
Packet retries
Sticky Client Behavior
AP transmit power is too high
Wrong dbm configured in Roam SNR
Association Steering is enabled
Device continues using distant AP
Signal becomes weak but still connected
Roaming decision delayed
Coverage Gap
If AP spacing is too large:
Device may lose connection before discovering next AP
Temporary disconnect occurs.
Channel Interference
If neighboring APs use the same channel:
Increased interference
Higher packet retry rate
Slower roaming decisions.
Detailed Troubleshooting Procedure
Step 1 – Confirm Roaming Pattern
Verify the issue occurs only while moving between APs.
Check:
Does connectivity drop while walking?
Does device reconnect automatically?
Do stationary devices work normally?
If yes, roaming behavior is likely the cause.
Step 2 – Identify Connected AP
In the Pronto controller:
Check which AP the client is connected to.
Verify:
Client remains connected to AP even when closer to another AP
Client does not switch to nearest AP
This indicates delayed roaming. (Physical assessment may require)
Step 4 – Review AP Channel Allocation and usages
Ensure adjacent APs are allocated with correct and conjunction free channels
Recommended configuration:
2.4 GHz
Channels 1, 6, 11
5 GHz
Channels 36, 40, 44 etc
Use NoN-DFS channels.
Step 5 – Check Transmit Power
If AP transmit power is too high:
Coverage areas overlap excessively
Devices delay roaming
Reduce transmit power gradually:
High → Medium → Low
Resolution Steps
1. Optimize AP Placement
Install APs in central coverage areas
Maintain consistent spacing between APs
Avoid mounting near metal structures or kitchen equipment
2. Adjust Channel Planning
Assign non-overlapping channels
Avoid same channel on neighboring APs
Reduce RF interference
3. Optimize Wireless Bands
Encourage use of 5 GHz band
Reduce dependency on crowded 2.4 GHz
4. Optimize Power
Increase/Reduce power based on on site assessment to avoid strong signal overlap
Set power to broadcast optimal signal in overlap area to provide smooth AP roaming
Validation After Fix
Confirm the following:
Devices roam between APs without disconnecting
POS remains connected while moving
Signal strength stable across coverage areas
Wireless retry rate reduced
POS transactions complete successfully
Test roaming by walking across the coverage area with a POS device.
Preventive Measures
To prevent roaming issues:
Maintain proper AP placement during deployment
Follow channel planning guidelines
Document AP locations on site floor plans
Test roaming performance during installation
Review wireless performance periodically