In networking architecture, point-to-point (P2P) links are used to interconnect two Layer 3 devices, such as a pair of Juniper MX series routers. Because these links only involve two endpoints, using a large subnet mask would result in wasted IP addresses. The standard historical prefix for a P2P link that provides exactly two usable host addresses is /30.
A /30 subnet mask (255.255.255.252) reserves 2 bits for the host portion. Applying the usable host formula ($2^2 - 2$) results in 2 usable addresses. In the case of 192.168.1.0/30:
* 192.168.1.0 is the Network Address.
* 192.168.1.1 is the first usable host address (assigned to Router A).
* 192.168.1.2 is the second usable host address (assigned to Router B).
* 192.168.1.3 is the Broadcast Address.
While modern Junos OS versions also support /31 masks for point-to-point links (which eliminate the network and broadcast address overhead to provide two hosts), the /30 mask remains the classic and most widely recognized answer for providing " only two usable host addresses " within the standard subnetting framework.
Using /30 ensures compatibility across all legacy and multi-vendor environments while precisely meeting the connectivity requirements of a dedicated link between two interfaces.
Reference: Networking Fundamentals, IPv4 Subnetting, Point-to-Point Links.

The forwarding table in a network device requires specific information to efficiently forward traffic toward its destination. This includes the next hop IP address, which indicates the next router or device in the path to the destination. The outgoing interface name identifies the physical or logical interface through which the packet should be sent to reach the next hop. Lastly, the next hop MAC address is crucial for Layer 2 forwarding decisions, allowing the device to encapsulate the IP packet in a frame that can be understood by Ethernet or other Layer 2 protocols. OSPF metric values and BGP local preference values are used in the routing decision process to select the best path and populate the forwarding table but are not directly used by the forwarding table to forward traffic.

The load override terminal command replaces the entire candidate configuration with the new configuration being entered, making it suitable for loading a large hierarchical configuration and discarding the existing one.

A /30 subnet provides 4 total IP addresses, with 2 usable host addresses, making it suitable for point-to-point links.

Static routes have a default preference value of 5 in Junos OS, making them more preferred than most dynamic routing protocols such as OSPF (10) or BGP (170), except for directly connected routes.