Use different SSIDs for 2.4G and 5G WLAN but allow access to each other

DrayTek VigorAP provides SSID isolation. It blocks the communication between wireless clients on different SSID for security reasons, even if the SSIDs are on the same subnet. But for dual-band models, Network Administrator can allow access between the SSID on different bands, even if the name is different.

NOTE: Wireless clients connecting to the identical SSID are always allowed to communicate with each other, even if they are on different bands. But clients on the same band but different SSID is always blocked from each other.

To allow communication between clients on different bands, disable the Isolate 2.4GHz and 5GHz bands option on Wireless LAN >> Advanced Setup page, as illustrated below.

Case 1: Isolate 2.4GHz and 5GHz bands Enabled

Figure a. SSID names on 2.4G and 5G are identical, so clients in 2.4G and 5G can communicate with one another.
Figure b. SSID names on 2.4G and 5G band are different, so clients in 2.4G and 5G cannot communicate with one another.

Case 2: Isolate 2.4GHz and 5GHz bands Disabled

Figure a. SSID names on 2.4G and 5G are identical, so clients in 2.4G and 5G can communicate with one another.
Figure b. SSID names on 2.4G and 5G band are different, but clients in 2.4G and 5G can still communicate with one another.