If you’ve ever dealt with teachers complaining that their laptops drop the connection while moving between classrooms, you know the frustration of Wi-Fi roaming. In a recent webinar from Wyebot, Sales Engineer Jacob Wilson breaks down why this happens and, more importantly, how you can fix it – or have Twotrees fix it.

The Golden Rule: It’s the Client’s Choice

The most critical takeaway (3:15) is that roaming is a client-side decision. Your access points (APs) don’t actually “move” a device; the device’s own driver monitors signal strength (RSSI) and decides when to jump to a new AP. If a device seems “sticky,” it’s usually because it hasn’t hit its internal threshold to start the scan-and-reconnect process yet (8:00).

The roaming process is entirely a client-side decision (3:15). Your wireless access points (APs) do not push the device to move; instead, the device’s Wi-Fi driver constantly monitors its environment and determines when to disconnect from one radio and join another (3:20).

The Roaming Decision Tree

Every client follows a standard decision loop to maintain a stable connection (4:45):

1. The Roaming Trigger: The process starts when the device hits a specific threshold. While most commonly based on Received Signal Strength Indicator (RSSI) (6:35), some modern drivers also consider:
   • Signal-to-Noise Ratio (SNR): The clarity of the signal above background interference (6:54).
   • Data Rates: If the connection speed (MCS rate) drops below an acceptable level (7:00).
   • Beacon Loss: Detecting that the current AP is no longer audible (9:55).
2. Discovery (Scanning): The client scans for other APs within the same Extended Service Set (ESS) to see what is available (11:23). This can be passive(listening for beacons) or active (sending probe requests) (12:05).
3. Ranking and Selection: Once the client has a list of potential candidates, it ranks them based on proprietary logic (19:07). This is where different manufacturers (e.g., Apple vs. others) may behave differently (7:37).
4. The “Go/No-Go” Decision: The client evaluates if the new AP is significantly better than the current one (24:49). This is a critical step to prevent “ping-ponging,” where a device rapidly jumps between two APs due to minor signal fluctuations (25:05).

Why Clients Seem “Sticky”

If a device stays connected to an AP even while you move closer to a new one, it is likely because the device hasn’t yet hit its internal trigger threshold (8:56).

• Threshold Gaps: For example, Apple devices are known to have conservative triggers (often around -70 to -75 dBm) (8:16) and require an AP to be roughly 8–12 dB stronger than the current one before committing to a roam (25:59).
• Vendor Logic: Since these roaming algorithms are generally proprietary and unpublished, different client drivers will naturally favor different APs even when standing in the same spot (7:14).

Roaming Criteria is often not well documented

A key takeaway from the video is that while roaming logic is a client-side process, it is rarely transparent (3:15). Understanding why a device decides to roam is often treated as a “black art” because most vendors do not publicly document their roaming algorithms, leaving network administrators to rely on trial-and-error and guesswork (7:11).

The Exception: Apple’s Documentation

Apple stands out by providing clear, detailed documentation on their roaming criteria (7:37). This transparency is a massive help for IT professionals because it removes the mystery for a significant portion of their client base:

• Thresholds are clear: Apple explicitly states that their devices typically enter the roaming process when signal strength hits -75 dBm for laptops and -70 dBmfor mobile devices like iPhones (8:09 – 8:36).
• Predictable behavior: By knowing these specific triggers, admins can design their networks with confidence, knowing exactly when those devices are expected to start looking for a new access point.
• The “Delta” Requirement: Apple even explains the “go/no-go” logic, noting that an access point usually needs to be 8 to 12 dB stronger than the current connection before the device will commit to a roam (25:59).

The “Black Art” of Other Vendors

In contrast, most other hardware vendors keep their roaming logic proprietary and unpublished (7:14). This creates several challenges for network managers:

1. Inconsistency: Without documentation, you cannot know if a device is staying connected to a weak signal because of a bug, a poor design, or simply because it hasn’t reached its specific (unknown) roaming threshold (8:56).
2. Troubleshooting is harder: Because there is no “standard” guide for other manufacturers, diagnosing why a specific laptop model seems “sticky” often requires custom data collection and extensive baseline testing (7:19).
3. Heavy Reliance on Tools: This is precisely why having diagnostic tools—like those offered by Wyebot—becomes essential for K-12 campus environments. Since you cannot rely on vendor documentation for every device, you must use sensors and agents to capture real-time data to see exactly why and when your devices are choosing to roam (54:06).

How Twotrees Optimizes Your Campus Network

At Twotrees, we know that relying on guesswork isn’t enough for a modern school environment. That is why we recommend, sell, install, and actively use Wyebot sensors to keep your campus network running at its best.

We install these sensors directly in your school’s environment to provide real-time visibility. Our team then uses the data from these installed sensors to:

• Troubleshoot: Quickly identify the root cause of connection drops and roaming failures.
• Tune: Adjust your network configuration to ensure roaming thresholds are optimized for your specific client devices.
• Optimize: Continuously validate your network design to provide consistent, high-performance coverage across the entire campus.

Why Your Network Needs Data-Driven Design

Jacob emphasizes that design is your best tool for influence (4:47). To minimize “ping-ponging” (where a device jumps back and forth between two APs), Twotrees uses the insights from Wyebot to help you:

• Right-Size Coverage: Avoid designing for the bare minimum number of APs. You want enough overlap so that clients have a healthy signal to transition to, but you must avoid excessive power levels, which can confuse clients (50:24).
• Leverage 802.11 Amendments: We ensure your network is configured to use K, V, and R amendments to make transitions smoother:
  • 11K (Neighbor Reports): Helps clients find nearby APs without wasting time scanning every channel (37:00).
  • 11V (BSS Transition Management): Allows APs to suggest a better roaming target to the client (39:56).
  • 11R (Fast BSS Transition): Essential for enterprise security, allowing devices to skip time-consuming authentication handshakes (43:16).

Stop relying on guesswork. As a Technical Director, your best approach is to collect actual data from your client devices (54:06). With Twotrees and Wyebot, you have a partner dedicated to monitoring and perfecting your wireless environment.