CCNA Cisco Certified Network Associate Study Guide - FTP Server

Glossary 667
control distribute VCC One of three control connections defined by
Phase 1 LAN Emulation; a unidirectional virtual control connection (VCC)
set up in ATM from an LES to an LEC. Usually, the VCC is a point-tomultipoint
connection. See also: control direct VCC.
convergence The process required for all routers in an internetwork to
update their routing tables and create a consistent view of the network, using
the best possible paths. No user data is passed during a convergence time.
core layer Top layer in the Cisco three-layer hierarchical model, which
helps you design, build, and maintain Cisco hierarchical networks. The core
layer passes packets quickly to distribution-layer devices only. No packet filtering
should take place at this layer.
cost Also known as path cost, an arbitrary value, based on hop count,
bandwidth, or other calculation, that is typically assigned by a network
administrator and used by the routing protocol to compare different routes
through an internetwork. Routing protocols use cost values to select the best
path to a certain destination: the lowest cost identifies the best path. Also
known as path cost. See also: routing metric.
count to infinity A problem occurring in routing algorithms that are slow
to converge where routers keep increasing the hop count to particular networks.
To avoid this problem, various solutions have been implemented into
each of the different routing protocols. Some of those solutions include
defining a maximum hop count (defining infinity), route poising, poison
reverse, and split horizon.
CPCS Common Part Convergence Sublayer: One of two AAL sublayers
that is service-dependent, it is further segmented into the CS and SAR sublayers.
The CPCS prepares data for transmission across the ATM network;
it creates the 48-byte payload cells that are sent to the ATM layer. See also:
AAL and ATM layer.
CPE Customer Premises Equipment: Items such as telephones, modems,
and terminals installed at customer locations and connected to the telephone
company network.