CCNA Cisco Certified Network Associate Study Guide - FTP Server

Glossary 663
channelized E1 Operating at 2.048Mpbs, an access link that is sectioned
into 29 B-channels and one D-channel, supporting DDR, Frame Relay, and
X.25. Compare with: channelized T1.
channelized T1 Operating at 1.544Mbps, an access link that is sectioned
into 23 B-channels and 1 D-channel of 64Kbps each, where individual channels
or groups of channels connect to various destinations, supporting DDR,
Frame Relay, and X.25. Compare with: channelized E1.
CHAP Challenge Handshake Authentication Protocol: Supported on lines
using PPP encapsulation, it is a security feature that identifies the remote end,
helping keep out unauthorized users. After CHAP is performed, the router or
access server determines whether a given user is permitted access. It is a
newer, more secure protocol than PAP. Compare with: PAP.
checksum A test for ensuring the integrity of sent data. It is a number
calculated from a series of values taken through a sequence of mathematical
functions, typically placed at the end of the data from which it is calculated,
and then recalculated at the receiving end for verification. Compare
with: CRC.
choke packet When congestion exists, it is a packet sent to inform a transmitter
that it should decrease its sending rate.
CIDR Classless Interdomain Routing: A method supported by classless
routing protocols, such as OSPF and BGP4, based on the concept of ignoring
the IP class of address, permitting route aggregation and VLSM that enable
routers to combine routes in order to minimize the routing information that
needs to be conveyed by the primary routers. It allows a group of IP networks
to appear to other networks as a unified, larger entity. In CIDR, IP
addresses and their subnet masks are written as four dotted octets, followed
by a forward slash and the numbering of masking bits (a form of subnet
notation shorthand). See also: BGP4.
CIP Channel Interface Processor: A channel attachment interface for use in
Cisco 7000 series routers that connects a host mainframe to a control unit.
This device eliminates the need for an FBP to attach channels.
CIR Committed Information Rate: Averaged over a minimum span of time
and measured in bps, a Frame Relay network’s agreed-upon minimum rate
of transferring information.