History Of Intermediary Devices Engineering Essay

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The company has five offices, with the head office in London and a port office in each of the following cities Southampton, Felix owe, Liverpool, and Aberdeen. The main Hub is located in the London office, and is linked to two switches one connecting the Administrative office which connects ten hosts that consists of workstations owned by the managing director, his personal assistant, the seven Admin assistants and the 4U database server. The other switch connects the insurers¿½ office which is made up of twenty two hosts that consists of the workstations of the twenty one insurers and the network printer. Meanwhile the other four port offices have an identical configuration which consists of a spoke router that is connected to the London Hub through an 8Mbps leased line and is linked through a 100base-T Straight Cable to a switch that contains thirteen hosts which consists of twelve staff and a network printer. The following is a detail of the equipment used:

2.1.1 Switch

The switches used for this network is the CISCO 2950 24 ports switch.

The CISCO 2950T 24 ports switch

This switch is used in each of the subnets in the London head office which are; the one connecting the Admin office to the London Hub and the second one connecting the insurers¿½ office to the main Hub it is also the same switch that is used in each of the port offices sub nets to connect the workstations and printer to each spoke router. This was chosen because of its proven reliability in terms of speed and there is also the availability of extra ports for future expansion in each of the subnets.

2.1.2 Routers

The two types of router used for this network are the CISCO 2811 Integrated Services Router and the Cisco 1841 Integrated Services Router. CISCO 2811 Integrated Services Router

This is the router used as the Hub in the London head office. The London Hub which is the central Hub to which all the Sub networks are linked through 8mbps leased lines. This Hub which is a CISCO2811 Integrated Services Router made up of expansion slots for high speed WAN interface cards which best suites the networks demands. The slot where used to connect the serial links from the fiber optic cables carrying the 8mbps leased lines from the fine Sub offices and also provides an outlet to the internet. Cisco 1841 Integrated Services Router

The other model of router used was the Cisco 1841 Integrated Services Router. This router was used as the Spokes for the four port offices and was configured to meet the needs of the port offices which had the thirteen hosts located in each of the offices (including one in the network printer) connected to it. The Cisco 1841 Integrated Services Router provides expansion slots for serial connectors, one console port, and one auxiliary port and also fast Ethernet ports to which the switch was connected. It also has the provision of extra slots to accommodate future expansions of the offices (like additional switches).

2.2 Addressing Scheme Used For the Sub-Networks

The addressing scheme used was repeated for all four port offices to allow for ease during maintenance for the network administrator. Each of the offices which had a requirement of 13 hosts where given a subnet mask of /27 and unique network address in the third octet with 3 through 6 for each office building, though the needed hosts were 13, the subnet provided a total of 30 usable host addresses which made it to have an extra of 17 free hosts but a 24 port switch and so there are extra 11 ports for future expansion in each of the port offices in terms of adding more systems as can be seen from the physical diagram (fig). As for the head office, different subnet masks of /27 for the insurers¿½ office and /28 for the admin office were used therefore making room for 2 more hosts in the insurers¿½ office (due to the 24 port switch) and an additional 4 hosts in the admin office (even though a 24 port switch was used) these leaves room for future expansion in the head office.

The WAN between the port offices (spokes) and the London Hub were sub netted to create a total of 8 sub networks thereby having a subnet mask of /27 and having the same address in the third octet which is 0 which is used as the link to the London Hub through the 8mbps leased lines connecting each of the port offices (spokes) to the main Hub in London.

As can be seen from figure 5 above, the insurers¿½ office is made up of 21 work stations and a network printer, with 10 on each side backing each other and a space of 1 meter between the two rows through which runs the cable raceway (the raceway is used to properly conceal the cables and prevent them from improper exposure) to which each work station is connected. The cables connecting the workstations to the switch are cat 5UTP cables (see figure 5) this can carry a bandwidth of 100Mbps which is very sufficient for the workstations and they are used to connect each workstation directly to the switch in a star topology. The same goes for the printer The length of these cables are all the same and is equal to 19m (see figure 5 ) and this is by far within the reach of the cables¿½ strength which is a maximum of 100m. This same type of cable is used for each of the workstations in the Admin assistant offices (B see figure 5), the Personal assistant¿½s office (C see figure 5) and the manager¿½s office (C see figure 5) and the length of these cables are all the same also which is 19.9m which is also a good length for the chosen type of cable, the lengths are all the same to allow for future adjustments or position of workstations. The cable connecting the server to the switch 1 is a Cat 5 (100Base-Tx) (see figure 5) this is used because it is faster 200 Mbps and is what will meet the need of the centralized 4U Database server that serves the whole network. The server room has been properly ventilated to meet the temperature requirements of the devices and has also the wiring closet in which the switch1, switch2 and the router are placed (see figure 5) this wiring cable has been strategically positioned to help minimal distance from the most distant device in the local network.

The cable used for each of the workstations is a UTP Cat 5s (see figure 6 ) this is because the requirement for this network does not exceed the 100Mbps that the cable is able to carry and also care has been taken to strategically place the wall mounted 24-port Switch which serves this local network so that there is a minimal distance covered between the farthest workstation and the switch which is 12.5m which is a far cry from the maximum length that this type of cable can carry which is 100m and therefore this will ensure optimum performance in the network (see figure 6 ). The UTP Cable Raceway has also been used as a housing to protect the cables that run from each workstation to the wall mounted 24-port Switch, this will overcome the common problem of copper cable which is interference and will also serve as a preservation from wear and tear (see figure 6 ).


Device Interface Subnet Mask Sub network Address Host IP/Host IP Range Broadcast Address

LondonHead Se0/0/0 172





Fa0/1 255.255.255240 ¿½

Fa0/0 ¿½

AberdeenPort Se0/0/0


FelixstonePort Se0/0/0


LiverpoolPort Se0/0/0


SouthamptonPort Se0/0/0


The above configuration has been used to meet the requirements of the Maritime Insurance Group (MIG) for a routable network comprising LAN and WAN. Care has been taken to leave room for future expansion in the network by leaving more ranges of the private IP provided. Furthermore, the equipment used has been carefully selected to provide a most efficient network. Considering also the issue of data security in the centralized 4U database server that is located in the server room at the London Head Office, the network Administrator has configured the server to provide different levels of privileges using the Operating System installed on the server and thereby has successfully blocked out any unwanted access to confidential / private data.