Local Area Network (LAN) Topology
You may hear the word topology used with respect to networks.
“Topology” refers to the physical
arrangement of network components and media within an enterprise networking
structure. There are four primary kinds of LAN
topologies: bus, tree, star, and ring.
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Networks |
Bus topology
is
•
A linear LAN
architecture in which transmissions from network
components propagate the length of the medium and are received by all other
components.
•
The bus portion is the common physical signal
path composed of wires or other media across which signals can be sent from one
part of a network to another.
Sometimes called a highway.
•
Ethernet/IEEE 802.3 networks commonly implement a bus topology
Tree topology
is
•
Similar to bus topology, except that tree networks
can contain branches with multiple nodes. As in bus topology, transmissions from one component propagate the length of
the medium and are received by all other components.
The disadvantage of bus topology is that if the connection to any one user is broken, the
entire network goes down, disrupting
communication between all users. Because of this problem, bus topology is rarely used today.
The advantage of bus topology
is that it requires less cabling (therefore, lower cost) than star topology.
Star topology
is a LAN topology in which endpoints on a network are connected to a common central switch or hub by
point-to-point links. Logical bus and ring topologies re often implemented
physically in a star topology.
•
The benefit of star topology is that even if the connection to any one user is broken,
the network stays functioning, and
communication between the remaining users is not disrupted.
•
The disadvantage of star topology is that it requires more cabling (therefore, higher cost)
than bus topology.
Star topology
may be thought of as a bus in a box.
Ring topology
consists of a series of repeaters connected to one another by unidirectional
transmission links to form a single closed loop.
•
Each station on the network connects to the network
at a repeater.
•
While logically a ring, ring topologies are
most often organized in a closed-loop star. A ring topology that is organized as a star implements a unidirectional
closed-loop star, instead of point-to-point links.
•
One example of a ring topology is Token Ring.
Redundancy is used to avoid collapse of the entire ring
in the event that a connection between two components fails.