How iOS decides which wireless network to auto-join

When auto-joining networks, iOS starts with the most preferred network, followed by private networks, then public ones.

When your iOS device evaluates service set identifiers (SSIDs) and determines which network to auto-join, it will try to connect to networks in this order:

  1. Your "most preferred" network
  2. The private network you most recently joined
  3. A private network
  4. A public network

Public networks are designed for general access in public places like a hotel, airport or coffee shop. Some other examples include Hotspot 2.0, Passpoint, EAP-SIM, or Wi-Fi connections that are provided by some cellular carriers and cable providers. Private networks are any other network, including those set up in homes and offices and the Personal Hotspot on your iOS device.

Known networks are "scored" based on your actions. If you manually switch to an SSID, its score increases. If you manually disconnect from an SSID, its score decreases. "Most preferred" networks have higher scores.

If iOS finds multiple networks after evaluating the above criteria, iOS prioritizes SSIDs by security level and chooses one based on the following order:

  Network Category Network Security
1 Private EAP
2 Private WPA
3 Private WEP
4 Private Unsecure/Open
5 Public HS2.0/Passpoint
6 Public EAP
7 Public WPA
8 Public WEP
9 Public Unsecure/Open

If iOS finds multiple networks of identical category and security level, it chooses the SSID with the strongest received signal strength indication (RSSI). Learn more about RSSI and wireless roaming for enterprise.

About auto-joining after a restart

After a restart, iOS Wi-Fi credentials are available only after you unlock your device. iOS waits until after the device is unlocked before auto-joining any nearby network.

Published Date:Thu Nov 09 17:38:04 GMT 2017