Network Design Models and LAN/WAN Implementation (Unit 15)

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Unit 15
Transport Network Design

Introduction
This assignment is performed to describe the various requirements and processes involved in
network design using LAN and WAN technology. It also describes the various issues related to
network design models and their solutions.
LO1
P1 Examine the network design models and features of scalable networks based on a
given set of business needs.
The internet is integrated into a business to address the advancements and meet their goals. For
this, the earlier created network models were not efficient enough as those were not meant for
business purposes. The later created network models are designed to be adaptable in business
approaches and are being used as per their requirements. To manage the processing of networks
for it's controlled and structured use in a business, multiple ways are offered to design a network
model. To process such network models, two common methods are used for analyzing the
working and design of the network-
The bottom-up method- This process mainly focuses on design models and in the selection of
networking technologies. This method can cause network design failure as the network does not
meet the applications or the business’s requirements.
The top-down method- This process is used to simplify the network design process in which
splitting of the design tasks is evaluated to implement more focus on the design scope for its
working in an efficient and controlled way. This helps the designers to view solutions related to
its design in the business.
Network design models-
It is the management and planning of the network services that are to be supplied all over the
devices in business. There are various types of network design models such as-
1. Two-tier model-

It contains two layers of networks i.e. distribution/core layer and access layer. This type of
network design model is generally used in small-scale business’s network system.
Figure 1: Two-tier model
2. Three-tier model-
It contains three layers of networks i.e. the core layer, the distribution layer, and the access
layer. It is generally used in large-scale business or enterprise network system. It is used
when there are multiple numbers of functioning distribution layers.
Figure 2: Three-tier model

3. Hierarchical design model-
It is a type of network design model in which three layers are present. The layers are similar
to the three-tier model. It differs from the three-tier model as in this type of network model, it
breaks down the complex network (flat) in many small and manageable network. Each and
every level present in this system has a different specific role. This model is highly preferred
as this model allows various alterations in the system such as- flexibility in selection of
software and hardware and also due to its properties to perform multiple tasks in the various
layers present in the system (Al-shawi, 2016).
Figure 3: Hierarchical model
The proposed business requirements can be achieved using the hierarchical design model as
this model is more advanced with respect to the other two models. This model provides
flexibility and scalability option for if in the future upgrade is required for the addition of
users or services without changing. This model also helps the network designer by detecting
the origin and flow of traffic in each layer separately. The designer can separately attend the
needs of each area making the design’s task easy and quick.

P2 Discuss LAN redundancy, bandwidth and load related issues and possible
solutions with reference to Layer 2 and Layer 3 of the OSI Mode
LAN redundancy- It is the process that makes a network fast and reliable. Redundancy can be
obtained using various physical links between the devices. This helps in keeping in the
continuation of the network when the primary path stops working. In layer 2, redundancy is
maintained by eliminating the formation of loops. Different paths are created and managed for
the uses when a link gets corrupted. These paths are selected on the basis of their ratings, the best
path is chosen first. If the primary path fails, alternate secondary path is automatically availed for
its uninterrupted operation. In layer 3, redundancy is maintained by the use of single virtual
routers to group all the physical routers. All the routers share the same IP and MAC address so
that if there is a router/ link failure, the secondary working physical router will automatically
activate and share the network in the same gateway IP and MAC address without causing any
network loss during the process (O'Keefe, 2018).
Bandwidth- It can be defined as the maximum data amount that is transmitted by an internet
provider in a certain time period. It is measured by calculating the bits per second (bps). In layer
2, bandwidth can impact in the incoming and transmission of data thus creating congestion and
decrease the network efficiency in the system. To address this issue, LAN topology can be
reconfigured by selecting root bridge to block the traffic that causes loop formation. This will
ensure the selection of the path with least resistance of data to the root bridge. In layer 3,
bandwidth impacts in the performance of the network thus causing delays during data
transmission. This issue can be addressed by decreasing the latency in the network system to
enhance the optimal performance of network design model (Walker and Curtis, 2018).
LO2
P3 Select LAN devices based on features and requirements and apply basic
configuration commands for network connectivity.
LAN (Local Area Network) devices are connecting devices that connects multiple computers
within a shared environment network in a workspace. A LAN device consists of both hardware
and software components for it to function successfully. Software components include the
network aware OS, drivers, and the other specialized codes for communications between

devices. The hardware components include the computers, routers, switches, hubs, cables, the
network interfaces, helping in the process of communication. Both software and hardware,
working together helps in the successful connectivity in a network.
In this assignment, the LAN devices selected are-
Router- A router is a networking hardware device that is used to establish communication
between the devices and the internet. It consists of software also known as firmware and other
hardware components for its functioning. It can be connected to network devices (computers)
using cables, FireWire, or USB devices. These routers can also be used as DHCP servers to issue
private IP configuration (Fisher, 2018).
Switch- It is a networking hardware device used for centralizing communications in between
multiple network devices in a single LAN connection. There are various types of switches
depending on their uses and functions such as- Unmanaged switch (used in homes and small
businesses), Managed switch, PoE switch, and Stackable switch. They also vary in ports with a
vast range in ports. In this assignment, multiport switch and normal switch with 24 ports are used
(Mitchell, 2018).
Hub- It is a networking device used in connecting multiple hosts and for data transferring. It
sends data in the form of packets which are then copied to all the ports connected in the network
design system. This device is less preferred as its issues such as congestion and slow data
transmission.
P4 Implement a LAN design with Layer 2 and Layer 3 redundancy using switch and
router redundancy protocols.
In this network design, use of various components is implemented such as routers, switches,
computers, and printers. Switches used in this network design are multiport type switch and
normal switch. Both the switches types used are 24-port type.

The network design used is in hierarchical model as there are multiple departments to be
connected in a single network system.
Multiport switch is used in the top-level (main organization) of the hierarchical design for the
successful connectivity of the respective departments. Each department is provided with normal
switches which are connected to the multiport switch outlet.
The finance department requires 9 computers and printers so the communication is established
using a normal switch of 24-ports. All the computers can be connected in the switch with option
for future addition of computers if required.
The Design department requires 40 computers and printers so the communication is established
using two normal 24-port switches. This ensures connectivity of all the computers with rooms
for more computers if added.
The sales department requires 65 computers and printers so the communication is established
using three normal 24-port switches. The computers can be connected to the ports for
establishing communication between the network system.
A total of 6 normal switches and a multiport switch are used in the designing of the network
system. The computer-computer communication in a department is established using netting
method.

Figure 4: Hierarchical design
Main
Organization
Multiport
switch
Finance
departent
switch 1
all the 9
computers
Design
department
switch 1
20
computers
switch 2
20
computers
Sales
department
switch 1
22
computers
switch 2
22
computers
switch 3
21
computers

Figure 5: DNS

Figure 6: Email

Figure 7: Email 2

Figure 8: FTP