NETWORKING
TOPOLOGIES
What
is a Topology?
The physical topology of a network refers to the configuration of
cables, computers, and other peripherals.
The logical topology of a network refers to the method used to pass
information between workstations.
Main Types of Physical Topologies
Star
Ring
Bus
Mesh
Hybrid
Point to Point
Point to Multi-Point
Client/Server
Peer to Peer
MPLS - MultiProtocolLabelSwitch
Considerations when choosing a topology
Star Topology
Star
Topology
A star topology is designed with each computer (file server, workstations,
and peripherals) connected directly to a central network called a
hub or a switch.
Data on a star network passes through the hub or concentrator before
continuing to its destination. The hub or concentrator manages and
controls all functions of the network. It also acts as a repeater
the data flow.
Advantages
of a Star Topology
• Easy to install and wire.
• No disruptions to the network then connecting or removing
devices.
• Easy to detect faults and to remove parts.
Disadvantages of a Star Topology
• Requires more cable length than a linear topology.
• If the hub or concentrator fails, nodes attached are disabled.
• More expensive than linear bus topologies because of the cost
of the concentrators.
Ring Topology
Ring
Topology
A star-wired ring topology may appear (externally) to be the same
as a star topology. Internally, the MAU (multistation access unit)
of a star-wired ring contains wiring that allows information to pass
from one device to another in a circle or ring. The Token Ring environment
uses a star-wired ring topology.
Ring-All computers or network devices are attached directly to each
other in a ring fashion. An example is an FDDI (fiber distributed
data interface) network, where all the hubs connect to each other
in a ring or a token ring network.
Advantages
of a Ring Topology
• Easy to install and wire.
• Equal Access to devices no one computer will use all the bandwidth
• Easy to detect faults and to remove parts.
Disadvantages of a Ring Topology
• Slow since signals goes in sequential order
• If the MAU or concentrator fails, nodes attached are disabled.
• Single break in cable can disrupt the flow of network
Bus Topology
Bus
Topology
A bus topology consists of a main run of cable with a terminator at
each end. All nodes (file server, workstations, and peripherals) are
connected to the linear cable. 10Base is an example of a network that
would use a bus topology.
Advantages
of a Linear Bus Topology
• Easy to connect a computer or peripheral to a linear bus.
• Requires less cable length than a star topology.
• Cheaper compared to start topology
Disadvantages of a Bus Topology
• Entire network shuts down if there is a break in the main
cable.
• Terminators are required at both ends of the backbone cable.
• Difficult to identify the problem if the entire network shuts
down.
• Not meant to be used as a stand-alone solution in a large
building.
Mesh Topology
Mesh
Topology
A mesh topology combines characteristics of bus, ring and star topologies.
It consists of groups of star-configured workstations connected to
a linear bus backbone cable and ring networks . Mesh topologies allow
for the expansion of an existing network, and enable companies to
configure a network to meet their needs.
Internet is the most famous example of a mesh topology
Advantages of a Mesh Topology
• Point-to-point wiring for individual segments. (redundant)
• Supported by several hardware and software venders.
Disadvantages of a Mesh Topology
• Overall length of each segment is limited by the type of cabling
used.
• If the backbone line breaks, the entire segment goes down.
• More difficult to configure and wire than other topologies.
Considerations When Choosing a Topology:
• Money. A bus network may be the least expensive way to install
a network; you do not have to purchase concentrators.
• Length of cable needed. The bus network uses shorter lengths
of cable.
• Future growth. With a star topology, expanding a network is
easily done by adding another concentrator.
• Cable type. The most common cable in schools is unshielded
twisted pair, which is most often used with star topologies.
Topology
