keep increasing the hop count to particular networks.
To avoid this problem, various solutions have been
implemented into each of the different routing proto-
cols. Some of those solutions include defining a maxi-
mum hop count (defining infinity), route poisoning,
poison reverse, and split horizon.
ther 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.
tomer locations and connected to the telephone com-
pany network.
accept a connection setup request, blocking the
request. The path is rolled back to an intermediate
node, which then uses GCAC to attempt to find an
alternate path to the final destination.
a calculation by dividing frame contents with a prime
binary divisor and compares the remainder to a value
stored in the frame by the sending node. Contrast
with: checksum.
802.3 committee. Each device senses the cable for a
digital signal before transmitting. Also, CSMA/CD
allows all devices on the network to share the same
cable, but one at a time. If two devices transmit at the
same time, a frame collision will occur and a jamming
pattern will be sent; the devices will stop transmitting,
wait a predetermined amount of time, and then try to
transmit again.
phone loop. Frequently referred to along with the data
service unit as CSU/DSU. See also: DSU.
source user-network interface (UNI) and the corre-
sponding cell entry event at the destination. The CTD
between these points is the sum of the total inter-ATM
transmission delay and the total ATM processing
delay.
leading edge exits the switch at the output port before
the packet finishes entering the input port. Frames will
be read, processed, and forwarded by devices that use
cut-through switching as soon as the destination
address of the frame is confirmed and the outgoing
port is identified.
LECs in ATM and one of three data connections
defined by Phase 1 LAN Emulation. Because data
direct VCCs do not guarantee QoS, they are generally
reserved for UBR and ABR connections. Compare
with: control distribute VCC and control direct VCC.
lates packets from the Network layer and prepares the
data for transmission on a network medium.
a previously established virtual circuit. IP datagrams
have become the primary information unit of the
Internet. At various layers of the OSI reference model,
the terms cell, frame, message, packet, and segment
also define these logical information groupings.
data over a given physical link and compares some-
what to the Data-Link layer of the OSI model.
across a physical link and is primarily concerned with
physical addressing, line discipline, network topol-
ogy, error notification, ordered delivery of frames,