Troubleshooting Remote Access Networks (CCIE Professional Development)

RFC 1661. "The Point-to-Point Protocol (PPP)." W. Simpson, Editor, 1994.

RFC 1332. "PPP Internet Protocol Control Protocol (IPCP)." McGregor, G. 1992.

Cisco Systems, Inc. CCIE Fundamentals: Network Design and Case Studies , Second Edition. Cisco Press, 2000.