1. Point to Point Protocol
By Bill Reed
PPP
Point to Point Protocol

2. PPP Point to Point Protocol is an encapsulation standard.
By Bill Reed
PPP
Point to Point Protocol is an encapsulation standard.
Major standard for modem based communication.
PPP is in reality a suite of protocols not a single entity.
PPP resides at layer 2 of the OSI model.

3. By Bill Reed

4. PPP Point to Point Protocol suite includes:
By Bill Reed
PPP
Point to Point Protocol suite includes:
LCP – Link Control Protocol
NCP – Network Control Protocol
PAP – Password Authentication Protocol
CHAP – Challenge Handshake Authentication Protocol

5. PPP Point to Point Protocol supports;
By Bill Reed
PPP
Point to Point Protocol supports;
Multiplexing of multiple upper layer protocols
Error detection (FCS)
Tunnelling using (L2TP or PPTP)
A range of layer 1&2 technologies
(X.25, ATM, Frame relay & serial)
Bandwidth Allocation Protocol (BAP)
Dynamic assignment of IP addresses

6. By Bill Reed
PPP
PPP uses HDLC (High level Data Link Control) as the basis for data encapsulation over point to point links.
PPP uses LCP (Link Control Protocol) for the establishment, configuration and testing of connections.
PPP uses multiple NCPs to allow simultaneous use of multiple network layer protocols
( IPCP for IP & IPXCP for IPX ).

7. PPP By Bill Reed Session Establishment; 1. Link is setup
2. Link is tested (optional phase)
3. Negotiation, configuration
4. Termination

8. PPP By Bill Reed Link Establishment
Establishing node sends a series of LCP frames which are used to configure and establish the data link.
2. Link Quality Determination (Optional)
Testing takes place to determine if the link is of sufficient quality to support network layer protocols.
3. Network layer protocol negotiation
Originator sends NCP frames to choose network protocols and configure the protocols chosen.
4. Termination of the link
The link remains open until LCP or NCP frames close the link, or an external event forces the termination of the connection.

9. PPP Authentication By Bill Reed Authentication is optional
If used authentication occurs between phases 2 and 3 of the link establishment process
PPP supports either PAP or CHAP authentication
PAP authentication
Two way handshake
Password sent in plain text
Susceptible to playback attacks
CHAP authentication
Three way handshake
Uses variable challenge value to guard against playback attacks

10. Authentication configuration
By Bill Reed
PPP
Authentication configuration
Router(config)#username name password secret
Name indicates the hostname of the remote router it is case sensitive.
Secret when using Cisco equipment the Secret password must be the same on both ends of the connection.
Router(config-if)# encapsulation ppp
Router(config-if)# ppp authentication option
Option can be chap, pap chap, chap pap, pap
Router(config-if)# ppp pap sent-username username password password
Router(config-if)# ppp chap hostname hostname
Router(config-if)# ppp chap password secret