where circuit switching of subscriber lines occurs.
other through an internetworking device. A collapsed
backbone can be a virtual network segment at work in
a device such as a router, hub, or switch.
the physical media, the frames from each node collide
and are damaged. See also: collision domain.
are propagated by hubs and repeaters, but not by LAN
switches, routers, or bridges. See also: collision.
metric to find the best path to a remote network.
IGRP and EIGRP both use bandwidth and delay of
the line by default. However, Maximum Transmis-
sion Unit (MTU), load, and reliability of a link can be
used as well.
Cisco routers function during initialization. In hard-
ware, the bit position is set using a jumper. In soft-
ware, it is set by specifying specific bit patterns used to
set start-up options, configured using a hexadecimal
value with configuration commands.
ing the system. Lower-priority traffic is discarded at
the edge of the network when indicators signal it can-
not be delivered, thus using resources efficiently.
little or no traffic successfully arrives at destination
points. It usually happens in networks made of
switches with ineffective or inadequate buffering
capabilities combined with poor packet discard or
ABR congestion feedback mechanisms.
will give you the connections a local router will have
to a remote router. The show users command will
show the connection IDs of users telnetted into your
local router.
effort delivery, not reliable. Contrast with: connec-
tion-oriented. See also: virtual circuit.
Uses flow and error control for reliable data transfer.
Contrast with: connectionless. See also: virtual circuit.
face capability.
tual control connection (VCC) established in ATM by
an LEC to an LES. See also: control distribute VCC.
rectional virtual control connection (VCC) set up in
ATM from an LES to an LEC. Usually, the VCC is a
point-to-multipoint connection. See also: control
direct VCC.
ate a consistent view of the network, using the best
possible paths. No user data is passed during a conver-
gence time.
tain Cisco hierarchical networks. The core layer passes
packets quickly to distribution-layer devices only. No
packet filtering should take place at this layer.
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 des-
tination: the lowest cost identifies the best path. Also
known as path cost. See also: routing metric.