Problem Statement
Glob-i-FMC is a UK based Financial Management Consultancy Company having its branches in operation over many countries in Europe, Asia and Australia. Recently the company has been successful to obtain the management consultancy of two major national banks in Japan. In line with this, next month the company is going to establish a Tokyo based office consisting of admin, accounts, finance, research department each consisting of 15, 18, 42 and 35 employees respectively. The proposed site consisting of four floors in a multi-storeyed building has already been acquired in the heart of the city: Produce a plan & design document to set-up a network equipping the proposed office with a file server, intranet server, mail server and connectivity to the head office. Additionally, document a list and specification of the required network technologies, network hardware etc.
Plan -Various factors to keep in mind
1) Covering all requirements
2) Feasibility
3) Cost of setting up the networks and maintenance
Design
1) Topologies:
The main office in UK is the centre or hub, which is connected to the other branches. Assuming that there is no direct connection between other offices, the outline is best suited for a star topology. The high level network design for the given problem is as shown. The International Office is the hub that connects all the branches to the main branch in UK.
High level Network Design: This covers the networking between the two countries using internet.
Figure 1: High level network topology
Within the new office however, the network topology may be mixed: All devices in a particular department (there are 4 departments) need to be connected to each other (mesh topology), and each mesh must be connected to the switch (Ethernet) that connects the LANs and the main switch to the International Office Network. This is as shown in Figures 2 and 3. Further, the sever switch in Figure 2 connects the file, mail and intranet servers with the Admin, Accounts, Finance, and Research LANs.
Figure 2: Topology
Figure 3: Low level network topology
2) Detailed Analysis:
Expected Number of users and setting priorities: At the new office, there are four departments: 15, 18, 42, and 35 employees in the Admin, Accounts, Finance, and Research departments respectively. Therefore the maximum number of people the network at any point in time is 110. Any network management process will be given the highest priority, any other network processes may get medium level priority, and processes like backup, file transfers, etc. can be given the least priority.
Network speed requirements: An average throughput of 20 mbps per user is good enough within each LAN. Similarly an average throughput of 10 mbps between LANs is more than sufficient to support the given requirements. The topologies discussed above are in line with the traffic expected. Performance will be smooth with this design.
Performance/Reliability: High standard LANs with 99.9% uptime and say an error rate of 0.001% can be designed to ensure quality.
Security Requirements: As in any global organization, the security needs of the Glob-i-FMC are important. In order to restrict any unauthorized users, a firewall can be set up. All the employees and any other authorized users must have set up password protected accounts with limited access.
Selection of network devices, switched network design, implementation and configuration:
1) Router: In this design, it is required to connect data between the Glob-i-FMC network and the other international offices, including the Tokyo branch, which all are assumed to work on the same network protocol. An appropriate CISCO router can be chosen.
2) Switches:
a) Main switch: This is required to connect the different LANs to the main router. This is preferably a multi layer switch (4-7) with 10/100 ports.
b) Secondary switch: This is switch/hub that connects individual LANs with each other, and to the main network. This is preferably a 24 Ethernet switch/hub with 10/100 ports.
3) Firewall: An application level firewall is preferable for security.
Configuring:
Individual LANs
A LAN or local area network can connect a relatively small area like the computers or work stations within a building or in a close vicinity. In this design, LANs are established to connect the different devices in a department, which may be on different floors of the same building. The LAN needs IP addresses in order to route or switch data between different nodes or destinations on the network.
The required 10Mbps LAN specification mentioned above can be met by using the Ethernet hardware. In order to configure each LAN, a NIC or Ethernet Network Interface Card for each device in the departments, a compatible hub, and cables are required.
The hardware required is already available. The appropriate server software needs to be configured in every department.
Switches
The main configuration settings to keep in mind are:
1) Set time
2) Define a default route (In this case the routes are simple, as shown in the network diagram)
3) Enabling Neighbour discovery: These are essential for network management and prove to be an important tool for accurately designing the topology of the network. The two most commonly used protocols are the Cisco Discovery Protocol (CDP) and the Link Layer Discovery Protocol (LLDP). Either may be chosen for this design.
4) Logging and Traps: Immediate notification of anything that happens on the network is important for proper monitoring, debugging, and alerting. A switch generally provides two ways to send data to a central place – these are using Simple Network Management Protocol (SNMP) and syslog respectively.
Alternative design:
1) The connectivity between departments can be using WLAN. However, there can be performance and quality related issues as, generally, wireless networks pick up more noise and have a higher interference from undesired signals, when compared to wired networks.
2) Secondly, in order to reduce cost, the primarily mentioned mesh topology within a department can be changed to a star topology, with an Ethernet hub, provided it meets with the demands of the organization and does not hinder smooth performance.
3) The departments themselves maybe connected by another LAN instead of the Ethernet hub.
4) Finally, the switches selected can be changed to fit the best possibility, if requirements are known in greater detail. For example, generally multi layer switches are referred to those that can handle both 2 and 3 layer switching. A 4-7 layer switch is also called a multi layer switch which is recommended in the initial design. However, the latter is more expensive and hence if reduced functionality is sufficient, the former may be used.
References
Kurose, J. F., & Ross, K. W. (2012). Computer networking: Pearson Education.
Kurose, J. F. Computer Networking: A Top-Down Approach Featuring the Internet, 3/E: Pearson Education India, 2005.
