CompTIA exam study guide presentations by instructor Brian Ferrill, PACE-IT (Progressive, Accelerated Certifications for Employment in Information Technology) "Funded by the Department of Labor, Employment and Training Administration, Grant #TC-23745-12-60-A-53" Learn more about the PACE-IT Online program: www.edcc.edu/pace-it

1. Network
topologies.

2. Page 2
Instructor, PACE-IT Program – Edmonds Community College
Areas of Expertise Industry Certifications
 PC Hardware
 Network Administration
 IT Project Management
 Network Design
 User Training
 IT Troubleshooting
Qualifications Summary
Education
 M.B.A., IT Management, Western Governor’s University
 B.S., IT Security, Western Governor’s University
Entrepreneur, executive leader, and proven manger
with 10+ years of experience turning complex issues
into efficient and effective solutions.
Strengths include developing and mentoring diverse
workforces, improving processes, analyzing
business needs and creating the solutions
required— with a focus on technology.

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– What is a topology?
– Peer-to-peer vs. client-server networks.
– Network topology models.
PACE-IT.

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Network topologies.

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A topology is basically a
map that can describe how a
network is laid out or how
the network functions.
The network topology can be described by either its
logical or physical properties. A logical topology
describes the theoretical signal path, while a
physical topology describes the physical layout of
the network.
Network topologies.

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Network topologies.

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– Are peer-to-peer and client-server really
examples of topologies?
» No. They don’t describe the signal path or the physical layout of
the network. And yes. They describe the how the network
functions.
– Peer-to-peer topology.
» Nodes control and grant access to resources on the network.
» No one node or group of nodes controls access to a specific type
of resource (no server is present).
» Each node is responsible for the resources it is willing to share.
– Client-server topology.
» Access to a network’s resources is controlled by a central server
(or servers).
» A central server (or servers) determines what resources get
shared, who is allowed to use the resources, and even when the
resources can be used.
– Hybrid topology.
» A combination of peer-to-peer and client-server networking.
Network topologies.

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Network topologies.

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The original Ethernet
standards established a bus
topology for the network—
both logically and
physically.
As time went on, the bus developed some
mechanical problems. That led to the development
of different physical topologies; however, the logical
topology remained the same in order to maintain
backward compatibility.
So, when discussing Ethernet networks, the logical
topology is always a bus topology, while the
physical topology can be different.
Network topologies.

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– Bus.
» The signal traverses from one end of the network to the
other.
» A break in the line breaks the network.
» The ends of the line must be terminated in order to
prevent signal bounce.
» The network cable is the central point.
– Ring.
» A bus line with the end points connected together.
» A break in the ring breaks the network.
» Often implemented with multiple rings (often two) that
counter rotate.
» Not very common in the LAN anymore, but is still used in
the MAN and the WAN (SONET especially).
Network topologies.

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– Star.
» Nodes radiate out from a central point.
» When implemented with a switch, a break in a segment
only brings down the segment.
» Most common implementation of the modern LAN.
– Mesh.
» Multiple connections between nodes on the network.
» Full mesh means that every node has a physical
connection to every other node.
• A full mesh topology is expensive to install because of
the amount of wiring and network interfaces required.
» Partial mesh means that there are multiple paths
between nodes.
Network topologies.

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– Point-to-point.
» Two nodes or systems connected directly together.
• Two PCs connected with a crossover cable creates a point-to-
point topology.
• Two routers connected via a serial link creates a point-to-point
topology.
» No central device is required to manage the connection.
» Is a common topology when implementing a WAN connection.
– Point-to-multipoint.
» A central device controls the paths to all other devices.
» Differs from a star in that the central device is intelligent.
» Wireless networks often implement point-to-multipoint
topologies.
• When the WAP sends, all devices on the network receive the
data; when a device sends, its data is only passed along to
the destination.
» Is also a common topology when implementing a WAN
connection.
Network topologies.

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Network topologies.
A topology is a map that can be used to describe the signal path or physical
layout of a network. The logical topology will describe the signal path, while
the physical topology is more of a wire schematic.
Topic
What is a topology?
Summary
In peer-to-peer networking, there is no central control of network resources.
Each node determines what it will share and what it will not share. In client-
server networking, there is central control of shared network resources with
a server controlling access. A network can have aspects of both and, when
this occurs, it is considered a hybrid topology.
Peer-to-peer vs. client-server
networks.
Ethernet networks are logical bus networks, regardless of the physical
layout. In bus topology, the signal goes end-to-end. Ring topology is a bus
with the ends connected. In a star topology, the nodes radiate out. Mesh
topology is multipath. Point-to-point topology is a direct connection. Point-
to-multipoint topology is a single point going to multiple nodes.
Network topology models.

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