You consult the OpenBSD version of the
ral man page
Code:
These are the modes the ral driver can operate in:
BSS mode Also known as infrastructure mode, this is used when asso-
ciating with an access point, through which all traffic
passes. This mode is the default.
IBSS mode Also known as IEEE ad-hoc mode or peer-to-peer mode. This
is the standardized method of operating without an access
point. Stations associate with a service set. However,
actual connections between stations are peer-to-peer.
Host AP In this mode the driver acts as an access point (base sta-
tion) for other cards.
monitor mode In this mode the driver is able to receive packets without
associating with an access point. This disables the in-
ternal receive filter and enables the card to capture
packets from networks which it wouldn't normally have ac-
cess to, or to scan for access points.