Wi-Fi Direct is Not Compatible With Wireless Network Interface Connections Using Dynamic Frequency Selection (DFS)

Dynamic Frequency Selection (DFS) is a channel allocation scheme for wireless communication designed to prevent electromagnetic interference with other technologies and services.  In many countries, regulatory requirements limit the number of 5 GHz channels available or place additional restrictions on their use because the spectrum is shared with other technologies and services. 

For certain frequency bands radar detection and avoidance capability is required when operating within the constrained bands. 

• DFS is a capability of the wireless AP (Access Point).  DFS support can be enabled or disabled on many APs.

• If a wireless AP detects a radar system on a channel with DFS enabled, the AP must announce to associated client devices that it is vacating the channel on which the radar is detected and the new channel to which it is moving. The client devices must immediately vacate the channel and are expected to associate to an AP on a different channel.

The Multifunction Printer (MFP) is capable of connecting to DFS wireless channels via the Wireless Network Interface.

The Wi-Fi Direct compatibility issue only occurs when both of the following are true:

• The MFP has Wi-Fi Direct and Wireless Network Interface enabled concurrently.

• The Wireless Network Interface connected to an AP operating on a DFS channel.

When supporting Wi-Fi Direct, the MFP acts as a Software Access Point and manages the Wi-Fi Direct connections and security.  The MFP’s Wi-Fi Direct implementation does not support the DFS capability and will not function on DFS channels. The MFP’s WiFi-Direct implementation uses the same channel as Wireless Network Interface if both features are enabled concurrently.  If the Wireless Network Interface is operating on a DFS channel, then WiFi-Direct is inoperable.

1. Confirm this interoperability issue is the problem by checking the Wi-Fi Direct WebUI page for a status message informing the SA of this interoperability issue.

2. Update the network configuration:
   

   1. Request DFS to be disabled on the wireless network the MFP is connected to.  DFS support can be turned off on the actual AP.  Then DFS frequencies/channels will not be supported.

   2. Connect the MFP to a 2.4GHz wireless network.  DFS frequencies are not supported on the 2.4GHz frequency bands.

   3. Switch the MFP to Ethernet instead of using the Wireless Network Interface.

If the problem persists, contact Support for additional assistance.