Networking Fundamentals Report: LAN and WAN Design for ARR Company

This report offers a comprehensive network design solution for ARR Company, a Melbourne-based business with multiple offices. It addresses the company's need for a reliable and secure network infrastructure, focusing on both Local Area Network (LAN) and Wide Area Network (WAN) design. The WAN design incorporates a Multi-Protocol Label Switching (MPLS) Virtual Private Network (VPN) with VPN IPsec for mobile access to ensure high performance and security across the geographically dispersed offices. The LAN design for the head office utilizes a switched LAN with Virtual LANs (VLANs) and a star topology, employing Ethernet and Fast Ethernet cables to connect workstations and switches. The report emphasizes cost-effectiveness, scalability, and security, including the implementation of a physical firewall. Detailed diagrams illustrate the proposed network architecture, including floor plans and network configurations, with references to relevant networking principles and technologies. The solution aims to meet the company's communication, file sharing, and intranet needs while optimizing network performance and security.

Networking Fundamentals
Assignment
Insert Authors Name/s per 1st Affiliation (Author)
(Affiliation): dept. name of organization
organization name/ acronyms
City, Country
E-mail adress
Keywords—WAN, LAN, network cabling, network topology
I. INTRODUCTION
Arr company, based in Melbourne has its head offices
located there on one building with different floors with
different departments occupying different floors. Further, the
company has offices in different geographical locations that are
not more than 70 kms away from the head office for a total of
six offices. This paper is a design solution that will enable all
employees on the six different offices with most user
requirements are met by servers located in their respective
offices. However, the employees need to communicate with
different offices to exchange files, use the intra net, and for for
e-mail, therefore a wired network will be sufficient. This paper
describes and details the design for a network that includes a
local area network (LAN) and a wide area network (WAN) to
meet the needs and requirements of the office; the design will
be made in such a way as to keep the costs down, following the
basic principles and rules of networking.
Q1 WAN DESIGN
The company has six different offices within the
Melbourne CBD and surrounding suburbs, with the maximum
distance between any two offices being 70 kms. The concerns
and issues to consider when designing the WAN include costs,
latency, uptime, security (very important), lead time to increase
the capacity on existing circuits and to implement new circuits,
jitter, and packet loss. These concerns mainly relate to file
transfers, sharing, and exchange between the different offices.
The different branches will also need to communicate with
each other using e-mail, and so require Internet connection
with reliable up-times. The concerns with the Internet include
uptime, security, latency, costs, packet loss, lead times for
implementing new circuits and lead times for increasing the
capacity of existing circuits; jitter is another concern [1]. With
these concerns in mind, the proposed WAN network design
will tackle these concerns while at the same time meeting the
requirements of the users.
In order to ensure security and file integrity during file
transfers, the WAN will be designed with a VPN (virtual
private network) [2], based on the MPLS (multi protocol label
switching) [3]. The MPLS VPN has been chosen as the default
method for the WAN because it is a highly flexible way for
routing several network traffic types and data transport, with
the MPLS being the backbone. This will ensure high latency
and security fr the network, as well as tackle jitter problems
[4]. The MPLS type to be used is the pseudo wire (point to
point) MPLS VPN that will use VLLs (virtual leased lines) to
provide L2 (layer 2) point to point connections between the
different office sites [5]. This type of MPLS has been chosen
because it can have TDM, ethernet, and ATM frames
encapsulated within them. Remote users will connect through
the VPN IPSec protocol and will connect via remote dial up
[6], such as workers on the move. The design is shown below;
Fig I
Q 2 LAN DESIGN
For the main office, there are three top floors in one
building in the Melbourne CBD with three departments;
marketing that has 20 work stations, general support with 32
work stations, and sales that has 38 workstations. The concerns
for the head office, and indeed other offices, is security, costs,
latency, and flexibility in the LAN network. To cater to the
issue of costs, instead of physical LAN network connecting all
the floors. The limitation of physical LANs is that scalability
becomes a challenge, and adding physical devices such as

switches work to increase costs, while costs is a major point of
concern for Arr. The head office network will be a switched
LAN that has VLANs; VLANs are implemented on the OSI
model Layer 2 that offers reliable data transit across a physical
link. The the data link layer is responsible for the network
topology, physical addressing, error notification, line
discipline, flow control, and ordered frame delivery. This layer
is termed the link layer, subdivided into the LLC sub layer and
the MAC sub layer [9]. Each floor ill have a physical switch,
connected to computers using a 10 Mbps Ethernet cable on
every floor.
Q3 LAN WIRING
The proposed LAN for the head office is a hybrid one with
physical Ethernet (fast Ethernet or Gigabit Ethernet) with
virtual LANs and switches to connect the different floors. A
fast Ethernet cable with 100 Mbps speed will then be used to
connect the switches on every floor to the main switch; using
this approach and the WAN design, related users even in
different physical locations can then be grouped into a single
sub network for easy operation and file sharing. The design for
the LAN and VLAN is shown in the figure below; from switch
D the connects to the other switches in each floor, there is a
connection to the router, that then connects to the WAN and
Internet. To ensure security, a physical firewall will be placed
between the switch D and the router (See Fig II), with
additional protection given through isolation of networks based
on user groups for the whole company. The computers in each
floor will be configured with a virtual LAN to reduce cabling
and hardware costs. Because there are different users, it is easy
to separate and isolate the users based on their needs, so that
general support, sales, and marketing so that every set of
related users are grouped together, without any physical
constraints [8]. A virtual LAN (VLAN) is made up of several
end systems in network equipment (switches or routers) or
hosts and all are members of a single logical broadcasting
domain; by using a VLAN, the physical limitations of the
broadcast domain are eliminated, hence ensuing uptime and
speed, and reduces chances of network congestion (intranet)
when there is exchange of large files, for example. The VLAN
will be supported in the LAN switches and each VLAN will
support a separate spanning tree. A single network
infrastructure will be used as the VLAN backbone to create
several multi layered or overlaid broadcast groups.
Q4 LAN TOPOLOGY
As for the head office, the proposed LAN network will be a
star topology’ the star topology has been chosen because it is
easy to add or remove users and extend the current circuit.
Further the star topology ensures that the network remains
resilient with a disruption in one connection not bale to affect
the other users within the network; it is also a relatively easy
network type to design and set up [7]. The main server
supports the company’s intranet while there is a separate mail
server to support the e-mail operations for the head office;
given that the design for the LAN is a VLAN, the mail server
can support users in other offices via the WAN. The proposed
design has the advantages of solving some of the concerns that
Arr faces, including security through the use of a VPN for the
WAN and implementation of a physical firewall in addition to
a software firewall in the main server at the head office. The
network will be fast, with 10 Mbps for the various floors and
related users and 100 Mbps fast Ethernet to connect the
switches in every floor to the main switch, ensuring the
network is always optimized, using virtualization will also
solve the issue of the number of switches; general support and
marketing have 32 and 38 workstations, which would require
additional switches.
Q5 FLOOR DIAGRAMS
The diagram for the and design for the head office LAN
located at Melbourne is shown in the figure II below; using the
VLAN eliminates the need for a lot of cabling while enabling a
fast and resilient Internet design both for the head office and
other branches.
Fig II
CONCLUSION
In providing a solution to the Arr company case study, a
design proposal was given for a WAN and LAN, with details
on the preferred cabling and topology for the LAN at the
company’s main offices that occupy three floors. The company
has three departments at its main offices that include marketing
that has 20 work stations, general support with 32 work
stations, and sales that has 38 workstations, and a total of six
branches located within a 70 km radius, which all need to be
linked with a high performance and low cost network solution.
The proposed solution for the WAN is an MPLS VPN with
VPN IPSec for mobile access; this enhances security, ensures
high performance, and at a minimal cost for its network of
branches. For the main offices, a VLAN built around a basic
physical LAN is proposed, with virtual switches to meet the
needs of all departments, using a star topology for the LAN
built using Ethernet 10 Mbps cables for computer connections
and 100 Mbps cables between switches in each floor and the
main controller switch, connected to a mail and general server
that connect with a router. The router provides connection to
the WAN and the Internet

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