point-to-point protocol (ppp)
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Point-to-Point Protocol (PPP)
ผศ.ดร. อนั�นัต์ ผลเพิ่ �มAsst.Prof.Anan Phonphoem, Ph.D.
anan@cpe.ku.ac.thhttp://www.cpe.ku.ac.th/~anan
Computer Engineering DepartmentKasetsart University, Bangkok, Thailand
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Point-to-Point Protocol
Internet
ISP
Many Internet users connect from home• Dial-up (Telephone line)• Leased line
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PPP Transition states
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PPP Layers
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PPP Layers
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PPP Layers (stacks) Link Control Protocol (LCP) Authentication Protocols Network Control Protocol (NCP) Bit Padding Digital Signals (DS) Services
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PPP Frame
Address: broadcast (avoid data link address)Control: U-frame format (HDLC)Protocol: defines data field
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Link Control Protocol (LCP)• establish/terminate• maintain• configuration
Code: 01=Config-request 02=Config-ack 05=Terminate-req …
Link Control Protocol (LCP)
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Common Options
Option Default
Maximum receive unit 1500
Authentication protocol None
Protocol field compression Off
Address and control field compression Off
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Authentication Mostly PPP is dial-up user. Validating the user is important Password Authentication Protocol (PAP)
2-way handshake Less secure
Challenge Handshake Authentication Protocol (CHAP) 3-way handshake More secure (no password sent)
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Password Authentication Protocol (PAP)
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PAP Packets
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Challenge Handshake Authentication Protocol (CHAP)
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CHAP packets
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PPP Transition states
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Internetwork Protocol Control Protocol (IPCP)
• Establish / Terminate @ network layer connection (IP)• Code 01:Configure-request 02:Configure-ack …
PPP communication
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PPP configuration
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PPP configuration
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Lab 3.3.2 PPP encapsulation 3.3.3 PPP authentication 3.3.5 Troubleshooting PPP
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