Network Software Architecture
Network Software Architecture
Network Software Architecture
Fundamental of Network
Internet and Intranet
Simplex
In simplex mode, the communication is unidirectional, as on a one-way
street. Only one of the two devices on a link can transmit; the other can only
receive. For example, Keyboards.
Half -Duplex
With half-duplex, communications happen in both directions, but in only
one direction at a time. When two computers communicate using half-duplex,
one computer sends a signal and the other receives; then, at some point, they
switch sending and receiving roles. For example, push-to-talk technology
(walkie-talkie).
Data Flow (Cont.)
Full-duplex
• workstation
Normally refers to any computer that is connected to the network and used by an
individual to do work.
(Peer-to-Peer) and (Client / Server) Architecture
• As discuss previous, the purpose of networking is to share resources, but
we don’t know how this is accomplished?
-This depends on the architecture of the network operating system
software. The two most common network types are peer-to-peer and
client/server.
Peer-to-Peer Architecture
In peer-to-peer networks, the connected computers have no
centralized authority. From an authority viewpoint, all of these
computers are equal. Each computer in a peer-to-peer network
can be both a client that requests resources and a server that
provides resources. There is no assigned role for any particular
device, and each of the devices usually runs similar software.
Peer-to-Peer Architecture
Client/Server Architecture
Client/Server Architecture
In this design, a client/server network uses a network
operating system designed to manage the entire network from a
centralized point, which is the server. Clients make requests of
the server, and the server responds with the information or access
to a resource.
Client/Server Architecture(Cont.)
Network Topology
• A topology is basically a map of a network. The physical topology of a
network describes the layout of the cables and workstations and the
location of all network components. Topologies can be either physical or
logical.
--Physical topologies
The term physical topology refers to the way in which a network is laid
out physically. Two or more devices connect to a link; two or more links form
a topology.
**This topology uses the least amount of cabling, but also covers the
shortest amount of distance.
**With a logical bus topology, messages pass through the trunk, and each
workstation checks to see if the message is addressed to itself. If the address of
the message matches the workstation’s address, the network adapter copies the
message to the card’s on-board memory.
Network Topology (Cont.)
• A bus topology has the following characteristics:
1. Is simple to install.
2. Is relatively inexpensive.
3. Uses less cable than other topologies.
--Star topologies are easy to install. A cable is run from each workstation to
the hub. The hub is placed in a central location in the office.
--Star topologies are more expensive to install than bus networks, because
there are several more cables that need to be installed, plus the cost of the hubs
that are needed.
Network Topology (Cont.)
The star topology has advantages:
1. New stations can be added easily and quickly.
2. A single cable failure won’t bring down the entire network.
3. It is relatively easy to troubleshoot.
If there are n computers, there will be (n * (n–1)) / 2 cables in the network. For
example, if you have five computers in a mesh network, it will use 5 * (5 – 1) /
2, which equals 10 cables. This complexity is compounded when you add
another workstation.
For example, your five-computer, 10-cable network will jump to 15 cables just
by adding one more computer. Imagine how the person doing the cabling
would feel if you told them you had to cable 50 computers in a mesh
network—they’d have to come up with 50 × (50 – 1) ÷ 2 = 1225 cables!
Network Topology (Cont.)
• Because of its design, the physical mesh topology is very expensive to install
and maintain.
• Cables must be run from each device to every other device. The advantage you
gain from it is its high fault tolerance.
• With a logical mesh topology, however, there will always be a way of getting
the data from source to destination. It may not be able to take the direct route,
but it can take an alternate, indirect route. It is for this reason that the mesh
topology is still found in WANs to connect multiple sites across WAN links. It
uses devices called routers to search multiple routes through the mesh and
determine the best path. However, the mesh topology does become inefficient
with five or more entities.
Network Topology (Cont.)
Mesh Topology
Thank You