GNS3 PPP protocol

Point to Point protocol
PPP frames are encapsulated in a lower-layer protocol that provides framing and may provide other functions such as a checksum to detect transmission errors. PPP on serial links is usually encapsulated in a framing similar to HDLC,
why do I use PPP encapsulation
If you want to operate with non-Cisco routers

PPP supports authentication protocols: Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).

router 1 configuration

R1(config)interface Serial1/0
R1(config-if)ip address 192.168.6.1 255.255.255.0
R1(config-if)no shutdown
R1(config-if)encapsulation ppp

router 2 configuration

R2(config)interface Serial1/0
R2(config-if)ip address 192.168.6.2 255.255.255.0
R2(config-if)no shutdown
R2(config-if)encapsulation

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