Must the IP addresses of interfaces on the two ends of a P2P link be on the same network segment

On an OSPF P2P network, if the link layer protocol is Point-to-Point Protocol (PPP) and different network segment addresses are configured on the interfaces on the two ends of the link, OSPF neighbors are in the Full state and forward traffic normally. If link layer protocol traffic is encapsulated over High-Level Data Link Control (HDLC) or another protocol, no neighbor relationship can be established. The difference in the OSPF neighbor relationship establishment with PPP and HDLC is that with PPP, the IP address of the peer can be negotiated. This allows the route to the peer to be obtained without additional operations.

In addition, on an OSPF broadcast network, NBMA network, or P2MP network, the IP address of the neighbor and that of the local interface must be on the same network segment.

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