HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual page 364

ADSL WAN Connections
PPPoA Overview
7-36
Router
Figure 7-12. Establishing a PPP Session
Step One. The devices exchange link control protocol (LCP) frames to
establish, configure, and control the link.
Step Two. If the devices are configured for authentication, they use one of
the following protocols to verify that they establish the PPP session with the
correct peer: Password Authentication Protocol (PAP), Challenge Handshake
Authentication Protocol (CHAP), or Extensible Authentication Protocol
(EAP). Exchanging authentication frames is optional.
The ProCurve Secure Router supports PAP and CHAP. For more information
about configuring PPP authentication on the ProCurve Secure Router, see
"PPP Authentication" on page 6-71 in Chapter 6: Configuring the Data Link
Layer Protocol for E1, T1, and Serial Interfaces.
Step Three. The devices use network control protocol (NCP) frames to
enable the exchange of Network Layer protocols, such as IP, across the link.
Step Four. The devices use PPP frames to transmit the actual data.
(For more information about establishing a PPP session, see Chapter 6:
Configuring the Data Link Layer Protocol for E1, T1, and Serial Interfaces.)
1. Link establishment
LCP
2. Authentication (optional)
PAP, CHAP, or EAP
3. Negotiation of network layer protocols
NCP: IPCP, BCP, IPXCP, and so on
4. Session established
PPP
Access
concentrator