Final answer:
The WLAN architecture where wireless nodes communicate directly with each other is called an ad hoc WLAN, which is also known as a peer-to-peer network or IBSS, different from infrastructure WLAN that involves a central access point.
Step-by-step explanation:
The WLAN architecture in which wireless nodes transmit directly to each other without the use of an access point is referred to as an ad hoc WLAN. This type of network is also known as a peer-to-peer network or independent basic service set (IBSS). In contrast, an infrastructure WLAN requires a central device, typically an access point, that manages network traffic and communication between wireless devices. The ad hoc mode is useful for establishing a network quickly when no infrastructure is available, and it is often used for temporary connections between devices.