Ppp - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Increasing Bandwidth
Configuring MLPPP
2-4

PPP

The two peers at either end of a point-to-point connection establish a PPP
session in four phases. (See Figure 2-2.)
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Figure 2-2. PPP Phases
1. Link establishment—Peers exchange Link Control Protocol (LCP) frames
to establish a link and negotiate the options for this link. These options
include the maximum receive unit (MRU), which determines the size of
the informational field in PPP frames, and the authentication protocol, if
used.
2. Authentication—Peers exchange frames for the authentication protocol
agreed upon during link establishment. (If they did not select authentica-
tion, they proceed to the next stage.) After both peers authenticate
themselves successfully, they proceed to the next stage.
3. Network Layer protocol—Peers exchange Network Control Protocol
(NCP) frames to negotiate which Network Layer (Layer 3) protocol the
PPP frames will encapsulate. NCP frames serve two functions: they
specify which Network Layer protocol will be used, and they negotiate
options for that protocol. For example, IP Control Protocol (IPCP) is the
NCP for IP. An IPCP frame can include IP addresses for DNS servers and
a request to compress the IP datagram (which will be the PPP information
field).
4. PPP—PPP frames carry the actual information being transferred over
the WAN link. In PPP terminology, this information is called a datagram.
After the two peers successfully exchange LCP frames, authenticate the
link (if authentication is configured), and negotiate the Network Layer
protocol, a PPP session is established. The peers can then exchange PPP
datagrams.
1. Link establishment
LCP
2. Authentication (optional)
PAP, CHAP, or EAP
3. Negotiation of Network Layer protocols
NCP: IPCP, BCP, and so on
4. Session established
PPP
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