The network circuit that only has two devices on it that can communicate is considered a point to point circuit. Point to point circuits do not require the use of ARP or broadcast traffic.
OSPF sets the network type of point to point by default for serial, GRE, and point-to-point frame relay interfaces. The Hello timer is set to 10 seconds.
As point to point networks do not use a DR/BDR, it has a ‘-‘ in the state field when running the command
show ip ospf interface