Data Communications and Networks: A Network Redesign for uSoft.com

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“DATA COMMUNICATIONS AND NETWORKS”
ASSIGNMENT-3
Author: Srikanth Beti
Date: 7 Feb. 19
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Summary
This report is the factual representation of the redesigned network for uSoft.com company.
There are various key terminologies discussed in detailed manner to provide the actual
redesigning for the company core network. The report contains information about the core
requirement of the network on different aspects such as IP addressing scheme, hardware and
software component support and end deliverables of services. There are several components
such as logical and physical designing of the network.
Logical design of the network includes all key components that defines the overall network
concept. The physical design of the network includes all the major hardware components that
are involved in the designing such as routers, switches, firewalls, IPS/ IDS systems, access
points, end devices, cables etc. The paper also does contain the information about the IP
allocation structure for the network of uSoft.com. The IP address scheme will not only meet
the current requirement of the company but will also be scalable for the future needs of the IP
addresses as per required.
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Contents
Summary....................................................................................................................................2
1. Introduction............................................................................................................................5
2. Organisational Description.....................................................................................................6
3. Analysis of User Requirements (Requirement engineering).................................................7
3.1 Working of Network.........................................................................................................7
3.2 Network Performance.......................................................................................................7
3.3 Network Security..............................................................................................................7
3.4Network Accessibility.......................................................................................................8
3.4 Network Quality of Service (QoS)...................................................................................8
3.5 Communication................................................................................................................8
4. Logical Design.......................................................................................................................9
4.1 Security.............................................................................................................................9
4.2 VTP and VLANs............................................................................................................10
4.3 Wireless connectivity and security.................................................................................11
4.4 Accessibility Service (SSH)...........................................................................................12
5. IP Address Allocation Plan..................................................................................................13
5.1 IP Address Calculation...................................................................................................14
6. Logical Network Diagram....................................................................................................16
6.1 WAN (Wide Area Network) Logical Design.................................................................16
6.2 LAN (Local Area Network) Logical Design..................................................................17
7. Physical Network Diagram..................................................................................................19
8. Conclusions..........................................................................................................................24
List of References....................................................................................................................25
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List of Figures
Figure 1: Firewall Logical design.............................................................................................9
Figure 2: VLANs Logical design.............................................................................................10
Figure 3: WLAN Logical design..............................................................................................11
Figure 4: Remote SSH access..................................................................................................12
Figure 5: WAN (Wide Area Network) Infrastructure..............................................................16
Figure 6: LAN (Local Area Network) Infrastructure...............................................................17
Figure 7: uSoft.com Network Design......................................................................................19
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1. Introduction
The project is to provide a practical real-world organisational report over the redesigning of a
company network. The redesigning of the complete network will not only provide assistance
for the company network but will also show the advanced features that will be either
upgraded or added to the existing network design of the company network.
The main aim of this report is to show the added components and feature to the existing
network of uSoft.com company, so that the redesigned network is more sustainable to the
company requirements. The upgraded functionalities of the network will overcome number of
aspects that were either lacking or downgrading (making flaws) the existing network. The
aspects which redesigned network will overcome are such as –
 Connectivity issues
 Manageability issues
 Security issues
 QoS (Quality of Service)
 Performance issues
 Communication Mediums
 Data security
 Network availability
 Network Scalability
All the above-mentioned points are featured and resolved in the redesigning phase of the
network.
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2. Organisational Description
The biomedical software development company “uSoft.com” is a medium size organization.
The company has 3 main branches which are Head Quarters, Branch A and Branch B. These
branches are over the Gold Coast Region for a distance from each other. The company is
already running over a preexisting network design. The company has expanded in the recent
years and has decided to redesign its existing network. The existing network design for Head
Quarter branch is not sufficient for the current scenario of the organization and is going to be
more expansive in the upcoming months.
Thus, the company requires a network redesigning to meet the current and future requirement
of network design. The design will include the complete change in the specification and
functionality of the existing network.
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3. Analysis of User Requirements (Requirement engineering)
The uSoft.com company is currently based over Gold Coast Region. The company is running
on old network. There are multiple domains of requirements that are on high demand such as
security, service providence, reachability, QoS (Quality of Service), redundancy,
accessibility, scalable, flexible, availability, communication over network etc. All such
requirements are discussed in detail as per the network requirement of uSoft.com (Marsan,
2008).
3.1 Working of Network
The redesigned network which is developed over the existing network is eligible to provide
higher end services such that it meets all the core network requirements of uSoft.com. There
are 3 different branches of the company that are located at different places. All these branches
intercommunicate with each other via WAN (Wide Area Network) infrastructure. For the
internal network of a branch LAN (Local Area Network) infrastructure is used. Private IP
addressing scheme is deployed over the network for as internal IP specification of the
network. Different services rudiments of the network are discussed below as:
3.2 Network Performance
The network performance is judged by various aspects of the redesigned network. For this
several components and practices on hardware and software are performed. By providing the
redundancy to the network, the designed network will be highly available so that, even if a
component (hardware) fails other paths are used for continuous network availability. Multiple
hardware like routers with HSRP (Hot Standby Router Protocol) can be implemented to
provide redundant network.
Other aspect of the performance of network is speed (bandwidth). For this cable such as Fast
Ethernet or Gigabit Ethernet cables are used to provide faster and reliable network service to
end users.
3.3 Network Security
For the security of the network there are various practices that can be implemented so to
secure the network from outer threats. Implementation of IPS (Intrusion Prevention System)
& IDS (Intrusion Detection System) systems can be deployed to provide authorization control
over the network. DMZs (Demilitarized Zones) can also be included in the network so that
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the private or internal network is out of reach from external users (public users). DMZ can
provide a rich security implementation to enhance the security practice. Other than these
Firewalls can be implemented over the different VLANs (Virtual LAN) so that access
controls can be implemented. Example of firewalls that can be deployed are such as Cisco
ASA Firewall, Juniper, Checkpoint, Paulo Alto etc (Genge, 2014).
3.4Network Accessibility
The network is highly accessible to the end user either in the network or from outside of the
network. For this there are two options such as Telnet and SSH (Secure Shell Login). Telnet
is less secure because it sends the data in a clear text format over the network but in case of
SSH the data transferred is encrypted and cannot be exposed easily. So for the network SSH
is the best option for network access.
3.4 Network Quality of Service (QoS)
Quality of Service (QoS) plays a vital role in the implemented network as it defines the
technical support for different network services running over the network. For the QoS for
uSoft.com company the network is compatible for TCP (Transmission Control Protocol) and
UDP (User Datagram Protocol). There are various services such as SSH, HTTP, SMTP, FTP
etc., services use TCP protocol & DHCP, NTP, NNP, TFTP, traceroute etc., services use
UDP protocol. By maintaining QoS to the network this is ensured that the network is able to
handle all types of data and service support over the network.
3.5 Communication
The network does include the VoIP functionality. Traditional telephones are very costlier for
a big company but the IP Phones are cheaper and configurable according to the requirement.
This service is configured such that the users in company are able to communicate each other
via the IP phones configured according to the network. For this Cisco’s IP Phones are
configured to provide VoIP service to the end users.
Required Components (Hardware and Software) for Head Quarters –
 WAN & LAN Infrastructure
 Redundancy (Redundant network design)
 Security (Firewalls, DMZs, IPS & IDS)
 Accessibility (SSH)
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 VoIP phones
4. Logical Design
The network design consists of different parts respective to each working and application.
Some practices are performed to the design more robust and practical for the real world
scenarios. Following are the concepts related to the designing –
4.1 Security
The company uses the local ISP for the internet connectivity and since, the internet is filled
with threats and unauthorised people it is mandatory to provide a firewall mechanism to
protect the internal network of the company from such threats.
For the security of the network there are firewalls deployed in the network which will filter
the traffic as per the policies set. All unauthorised traffic will be filtered and corresponding
actions will be taken to such activities.
Figure 1: Firewall Logical design
In figure 1, when the firewall receives the traffic from the router (gateway router), it is
thoroughly verified as configured. The traffic from the legitimate user is passed but the traffic
from unauthorised user is blocked and action is performed. By such implementation the
internal network is secured from outer threats of the network. For the configuration of the
firewall the basic application is ACL (Access Control Lists) (Bruno, 2010).
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4.2 VTP and VLANs
For the operations of multiple subnetworks in a same network design (LAN), there is a need
of distinguishing the different network on layer 2 bases. So there is the need of
implementation of VLAN (Virtual LAN) in the network to separate the networks over a same
switch.
Figure 2: VLANs Logical design
In figure 2, is the representation of the VLAN structure of the network. each department of
the company is assigned with its own subnetwork and these subnetworks must not collide on
layer 2 base. Different VLANs are created for each subnetwork assigned to a department.
There is a VTP (Virtual Trunk Protocol) server which is configured with all the information
of all VLAN. Other switches (access layer switches) are configured as client switches and the
VLAN information is passed to them.
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4.3 Wireless connectivity and security
The LAN network of the company involves wireless connectivity to the users that are in the
network range. Access Points are configured in the LAN to provide wireless connectivity.
Each department (on every floor) has set of wireless access points to provide end to end
connectivity between LAN and WLAN (Wireless LAN).
Figure 3: WLAN Logical design
In figure 3, there is an access point configured in the LAN network of a department in Head
Quarters. The security running over the access point is configured with WPA2-PSK protocol.
Access Point is named with a unique SSID name (like Department_A) and a passphrase is
also configured to authenticate the user trying to access wireless connectivity.
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4.4 Accessibility Service (SSH)
For the accessibility of the network from a remote location SSH (Secure Shell) service has
been configured. SSH is a tunnelling service which provides remote access to the target SSH
server (SSH device) device.
Figure 4: Remote SSH access
In figure 4, is a client PC from Branch A site which is accessing the remote access to the
terminal or GUI service of target PC (SSH Server) in Head Quarters branch via the SSH
service. There are 4 phases of the complete SSH tunnelling connection that are –
1. Client PC initiated the connection with the target PC
2. The target PC provides its public key to the client PC
3. Both the client and target PC negotiates the parameters and establishes SSH tunnel
between them
4. Client PC sends user credentials to the target PC for the destination user line access and
target PC verifies the credentials. If credentials are matches then access is provided else
rejected.
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