WiFi · Networking
Wi-Fi Roaming
The process by which a wireless device transitions from one access point to another as it moves through a space, ideally without dropping connections or interrupting ongoing sessions.
In a multi-AP environment, a device doesn't stay connected to one AP forever — as it moves, signal quality to the current AP degrades and a nearer AP becomes the better choice. Roaming is the handoff process.
Sticky client problem
The roaming decision is made by the client, not the AP. Some clients are "sticky" — they hold onto a weak signal from a distant AP rather than roaming to a closer one, even when the closer AP would give them much better performance. This is a common cause of poor Wi-Fi experience in larger spaces.
Modern APs combat this through 802.11v (BSS Transition Management), which allows the AP to suggest to a client that it roam to a better AP, and 802.11k (Neighbor Reports), which lets the client discover nearby APs without scanning. Controllers automate this.
802.11r — Fast BSS Transition
Standard roaming requires the client to fully re-authenticate with the new AP, which can take several hundred milliseconds and breaks VoIP calls and time-sensitive applications. 802.11r (Fast BSS Transition) pre-caches authentication information so the handoff takes milliseconds rather than hundreds of milliseconds. Essential for voice and video in roaming environments.
SSID consistency
For seamless roaming, all APs serving the same wireless network must broadcast the same SSID with the same security settings. Clients roam between APs transparently because from their perspective it's all the same network.