Installing and Administering PPP

Glossary 163
Glossary
Active-Open: an event internal
to the PPP configuration finite
state machine that causes PPP to
start sending Configure-Request
messages to the peer.
bps: bits per second.
Challenge Handshake
Authentication Protocol
(CHAP): a challenge-response
LCP authentication protocol
resistant to playback attacks.
CHAP runs after LCP negotiation
is complete but before any NCPs
are started.
CHAP: see Challenge Handshake
Authentication Protocol.
DNS: see Domain Name System.
Domain Name System (DNS):
the distributed host and network
name database system used to
translate between Internet
addresses and their associated
host and network names. RFC
1034 is an introduction to DNS.
RFC 1035 describes the protocols
and data types used.
FCS: see Frame Check Sequence.
File Transfer Protocol (FTP):
internet protocol, described in RFC
959, used to copy data files across
TCP/IP networks.
Frame Check Sequence
(FCS): the 16-bit field
transmitted after all data in a
frame but before the closing flag.
Its value is computed using the
data portion of the frame and a
binary polynomial, and its purpose
is to provide the receiver with a
fairly reliable check against data
corruption during transmission.
An ’FCS error’ indicates that a
frame was damaged in transit.
FTP: see File Transfer Protocol.
HDLC: hardware flow control: out
of band flow control defined in EIA
RS-232-D that provides
bidirectional flow control using
the Request to Send (RTS) and
Clear to Send (CTS) signals. The
DTE (typically a computer) asserts
RTS when it is able to accept
input, and the DCE (typically a
modem) asserts CTS when it is
able to accept input.
High-Level Data Link Control
(HDLC): a bit-oriented framing
and addresing scheme defined in
ISO 3309 that is used as the basis
for most modern synchronous
wide-area data communications
protocols, including PPP, X.25,
SNA, OSI, and Frame Relay.