PPP

Point to Point Protocol == dial up access (DSL) from client to ISP uisng PPPoE || PPPoA

PPP provides data-link connection between 2 routers, it can provide authentication, encryption, and compression featues.

And PPTP (point to point tunneling protocol) is for hosts, not for 2 routers ~

LCP (Layer2) to establish Link

LCP, Link Control Protocol to establish, configure, and test the link as well as negotiate settings, options and the use of features.

Layer3 config

• IPCP, Internet Protocol Control Protocol

• IPXCP, Internetwork Packet Exchange Control Protocol

• ATCP, AppleTalk Control Protocol

• IPv6CP, Internet Protocol Version 6 Control Protoco will see extended use in the future (when IPv6 replaces IPv4 as the dominant layer-3 protocol).

Establishment of PPP in Physical Network

• Serial Cable or Phone Line

• Smart Phone

• SONET (optical fiber)

• Special Radio Link

Life Cycle

1. dead

2. establish

3. auth using PAP

4. data transport while the network protocol invoked.

5. terminate

Auth

Peer routers exchange auth messages. Two auth choices are Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).

Auth's Work Principle

https://github.com/QueenieCplusplus/DataStorage_Hadoop#key-in-session-加密的安全通訊技術

Encrypto

https://github.com/QueenieCplusplus/Cipher_Crypto

Compression

Increases the effective throughput on PPP connections by reducing the amount of data in the frame that must travel across the link. Then decompress at destination.

PPP frame (within datagrame)

• Structure

flag	broadcast_addr	control	protocol	info	pad	Checksum	flag
begin & end	0xFF		PPP ID	datagram	opt

• Encapsulation

flag	broadcast_addr	control	protocol	info	pad	fcs