Intel ER8100STUS - Express 8100 Router Reference Manual page 21

PPP protocols
Link Control Protocol
(LCP)
Operation of PPP
9
PPP provides transport services for data packet delivery with low overheads and
high throughput. Frame checking at the link-level offers error detection, but error
recovery is taken care of by higher-layer network protocols.
The following diagram shows how the various PPP protocols are embedded:
Compression Internet Protocol
Control Protocol Control Protocol
(CCP) (IPCP)
Challenge Handshake Authentication
Network Control Protocols (NCPs)
LCP is the lowest layer in the PPP stack and runs on top of the High-level Data
Link Control protocol (HDLC) or Integrated Services Digital Networks (ISDN).
When the HDLC or ISDN protocol has established the link, LCP runs on top of it.
The following protocols form the basis of PPP:
Encapsulation
Network-layer protocols are encapsulated for transmission over WAN links.
Link Control Protocol (LCP)
The LCP takes care of the link connection.
Challenge Handshake Authentication Protocol (CHAP)
The Challenge Handshake Authentication Protocol (CHAP) is available to offer
security (encrypted password protection) against unauthorized access to a PPP
link.
Password Authentication Protocol (PAP)
The Password Authentication Protocol (PAP) is available as an alternative to
CHAP offering security (password protection) against unauthorized access to a
PPP link.
Encryption Control Protocol (ECP)
Data encryption is available when communicating over PPP links. The Encryp-
tion Control Protocol (ECP) negotiates and manages data encryption between the
devices over the link.
Internet Packet
Exchange Control
Protocol (IPXCP)
Encryption Control Protocol
(ECP)
Protocol (CHAP)
Link Control Protocol
(LCP)
Leased Lines Links
Point-to-Point Protocol (PPP)
Bridging
Control
Protocol (BCP)
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