Network Topologies Comparison
Presented by: Eng. Ahmed Atef Elnaggar
Supervisor: Prof. Shawkat K.Guirguis
Department of Information Technology, Institute of Graduate Studies and Research, University of Alexandria, Egypt.
Bus
Star
Ring
Token-ring
Tree
Mesh
Fully connected
Hybrid Mesh
Architecture
/Organization
is a network topology in which
there is a single line (the bus) to
which all nodes are connected, and
the nodes connect only to this bus.
This is a bus line going through a
city. The cable has a small cap
installed at the end, called a
terminator.
The
terminator
prevents signals from bouncing
back and causing network errors.
Like a series of pipes that water
travels through
A network topology in which
peripheral nodes are connected to
a central node(such as a hub,
switch,
or
router)
which
rebroadcasts all transmissions
received from any peripheral node
to all peripheral nodes on the
network, including the originating
node. All peripheral nodes may
thus communicate with all others
by transmitting to, and receiving
from, the central node only.
A network topology in which
every node has exactly two
branches connected to it.
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. point-to point links
in a closed loop.
Token Ring technology was
developed in the 1970s by IBM.
Token-passing networks move a
small frame, called a token, around
the network. Possession of the
token grants the right to transmit.
If a node receiving the token has
no information to send, it passes
the token to the next end station
and the process repeats itself.
Each station can hold the token
for a maximum period of time.
The nodes are arranged as a tree.
The
tree
topology
is
a
generalization of the bus topology.
The transmission medium is a
branching cable with no closed
loops. The tree layout begins at a
point known as the head end
(root), where one or more cables
start, and each of these may have
branches. The branches in turn
may have additional branches to
allow quite complex layouts.
A network topology in which there
are at least two nodes with two or
more paths between them.
A fully connected topology is a
network topology in which there is
a direct link between all pairs of
nodes. In a fully connected
network with n nodes, there are
n(n-1)/2 direct links. Synonym
fully connected mesh network.
is a combination of any two or
more network topologies in such a
way that the resulting network
does not have one of the standard
forms. For example, a tree network
connected to a tree network is still
a tree network, but two star
networks connected together
exhibit hybrid network topologies.
A hybrid topology is always
produced when two different basic
network topologies are connected
Advantages
*Easy to add stations
*Requires less cable length than a
star topology.-Easy to T.shoot
*If there is a problem with host
The rest of the N.W remains
operational, Inexpensive to Install
*Work well for small N.W
*Easy to install and wire.
*No disruptions to the network
when connecting or removing
devices.
*Easy to detect faults and to
remove parts.
*Computers are located close to
each other.
*Setup is easy. (no connector).
*The ring has no beginning, no
end no need terminators.
*troubleshooting easy.
*Data packets travel at great speed
*No collisions.
*Easier to fault find.
*No terminators required.
*Point-to-point wiring for
individual segments.
*Supported by several hardware
and software venders
*If a node fails, its connection is
isolated and the rest of the LAN
can continue onwards.
Most often used in WANs to
interconnect LANs.
Each node is connected to every
other node, It has Fault Tolerant..
Allows communication to continue
in the event of a break in any one
connection. Provides redundant
paths between devices
connects all devices to each other.
When every device is connected to
every other device, a failure of any
cable does not affect the network.
The mesh topology is used in
WANs that interconnect LANs.
It has Fault Tolerant and Multiple
paths .
*Often created when expanding an
existing network.
* Can use a variety of connection
devices.
*Larger networks, such as those of
corporations or universities, use
the hierarchical star topology.
Disadvantages
/Troubleshooting
*Backbone breaks, whole N.W
down. (No fault tolerant)
*Terminators are required at both
ends of the backbone cable.
*Sharing same cable slows
response rates.
*No longer recommended.
*Not meant to be used as a standalone solution in a large building.
*Difficult to isolate problems.
*Requires more cable length than
a linear and ring topologies.
*If the hub or concentrator fails,
nodes attached are disabled.
*More expensive than linear bus
topologies because of the cost of
the concentrators.
*Up to 24 computers per network.
*100 meters max. cable length
If there's a break in the cable or an
error in the network, information
continues to transfer through the
rest of the ring until reaching the
point of the break.
multiple stations share the ring,
medium access control is needed
to determine at what time each
station may insert frames.
*Requires more cable than a bus.
*A break in the ring will bring it
down.
*Not as common as the bus.
*Less device available.
*If the backbone line breaks, the
entire segment goes down.
*More difficult to configure and
wire than other topologies.
*transmission from any one station
can be received by all other
stations
*a mechanism is needed to
regulate transmission
*Expensive
*Difficult to install
*Difficult to manage
*Difficult to troubleshoot
*Complicated implementation.
*Requires more cable than the
other LAN topologies.
Troubleshooting is most difficult
in this topology because of the
variety of technologies.
Congestion control
/Information Transfer
(6) One computer at a time sends
information. Information goes
along the cable and the computer
accesses the information off the
cable
(5) All information passes through
the
central
(HQ)
network
connection.
where a single information source
communicates
directly
with
multiple clients. used in a
broadcast N.W
(2)Information goes in one
direction
(clockwise
or
counterclockwise)
around the ring and passes along
the ring until it reaches the correct
computer. no buffering at repeater
(1) A specially-formatted frame,
called a token, travels around the
ring, stopping at each host.. The
destination host takes the data out
of the frame. No data collisions.
(7) a transmission from any station
propagates throughout the medium
and can be received by all other
stations. . A host that is a branch
off from the main tree is called a
‘leaf’. Ex)DNS system.
(4)A few of congestion, direct
from source to destination except
the station with less connection
(3) Many
tolerance
(8) Often used across long
distances. Information transfer can
happen
in
different
ways,
depending on the other topologies.
Delay/Response time
(4) Delay cause broadcast
(2) Excellent in terms of distance
(3) OK.
(1) Not bad (No data collisions.)
(5) Possible traffic jams.
(6) Trade off with cost
(7) Too slow, add more links.
Common Cable
Coax - Twisted Pair - Fiber
.coaxial cable -Twisted Pair- Fiber
No more than 100 meters from the
computer to the connection device.
Twisted
pair.-Requires
more
cables than other topologies.
Twisted Pair
Overall length of each segment is
limited by the type of cabling
used. (Coax - Twisted Pair – Fiber)
All kind of cables that can be used with LAN and WAN
Cabling depends on the types of
networks. twisted pair, coax, fiber
Expansion
(3)you must shut down the N.W
and disconnect the cable from the
existing computers. More nodes
causes worse performance
Max. 4 repeaters,2500m,488 nodes
(2)Easy to expand Add a new
computer by plugging in a new
cable from the computer to the
connection device max 1024 nodes
(5)Cable between the computers
must be broken to add a new
computer, so N.W is down until
the new device is back online.
(4) The more workstations causes
slower the response time
Not very flexible or scalable
(1)The simplest to install and
extend extra Stations in a daisy
chain manner,
(6)
(7)difficult to Expand
Connection
devices
make
combining different networks and
different topologies easy.
Most networks implement today
Reliability
7) If cable fails, whole network
fails.
(5)Failure of a node not affect
other nodes, but. If HQ down,
whole N.W fails,
(4) Partitioned easily, but nodes
inside partitions still work.
(3) A single malfunctioning
workstation can disable the
network
(6) N.W partitioned easily, but
partitions still work.
(2)
(1)The most reliable one, doesn't
have single point of failure/attack
extremely rare.There are 4 models:
(Star-wired ring, Star-wired bus,
Daisy chained, Hierarchical)
Complexity
(8) The Simplest one(Used for
LANs)
(7) Very simple(Used for LANs)
(6) (Used for LANs)
(6) (Used for LANs)
(4) Used for WANs
(3) Used for WANs
(2) Used for WANs
(1)The most complicated one
Security
(4) Not secure cause broadcast
(2) ex) denial of service attack
(3)
(1)
(5)
6)A mesh needs secure links,
routing, and forwarding
6)
(8) The worst
Cost
(1)The cheapest N.W usually only
one continuous copper cable.
(4)Expensive due to costly
connection device.(Router,Switch)
(2) Fairly low
(3) Fairly low
(5)
(6)
(7)Expensive due to high cable
costs.
(8)Expensive, large, and usually
complicated.
Topologies
Logical Topologies
(i.e. virtual)
paths
with
fault
(8)The worst
Considerations When Choosing a Topology:
● Money. (A linear bus network may be the least expensive way to install a network; you do not have to purchase concentrators.)
● Future growth or Expandability. (With a star topology, expanding a network is by adding concentrators.
● Length of cable, Number and location of users. (The linear bus network uses shorter lengths of cable.)
● Cable or Wireless type. (The most common cable in schools is unshielded twisted pair, which is most often used with star topologies.)