OSI and TCP/IP model

There are different communication protocols used for connecting the host in the internet and it acts as a gateway for sending and receiving the data packets to the sender and the receiver connected in the network. The OSI model is developed to act as a reference model but the TCP/IP model is developed from the OSI model. There are four layers in the TCP/IP model whereas the OSI reference model uses seven layers for its operations. The OSI model is based on networking theory and thus it is considered as a theoretical model and it does not find its application in the internet. The TCP/IP model is a practical model and it is more reliable than the OSI model. The OSI model has strict boundaries and protocols but the TCP/IP adds flexibility to the network and only follows the general guidelines that should be met for the development of the network. The connectionless protocols are supported by the TCP/IP model but both the connectionless and the connection oriented protocols are supported by the OSI reference model.

The TCP/IP model have distinct presentation and session layers whereas the OSI layer only has a single layer known as the application layer. The TCP/IP model is a primitive one and the protocol were developed after the development of the model was completed and hence the model follows a protocol independent standard. On the other hand the OSI model development was done after the development of the protocols and the model follows the protocol dependent standards.

The table provided below provides the subnet mask calculation for the IP4 addressing mode with the IP as 192.168.0.0 and the number of addresses to be 24.

IP address	192.168.0.0 Save Time On Research and Writing Hire a Pro to Write You a 100% Plagiarism-Free Paper. Get My Paper
Class	C
Type	PRIVATE (For Use in a private network. Not routabel in the Internet [rfc1918])
Network	192.168.0.0
Bitmask	24
Netmask	255.255.255.0
Wildcardmask	0.0.0.255
host range	192.168.0.1- 192.168.0.254
broadcast address	192.168.0.255
total IP addresses	254
Short	192.168.0
integer ID	3232235520
hexadecimal ID I	0xc0a80000
hexadecimal ID II	3139322e3136382e302e30
binary ID	Top of Form Bottom of Form 11000000101010000000000000000000
in-addr.arpa format	0.0.168.192.in-addr.arpa
mapped IPv4 address	::ffff:c0a8:0000
6to4 prefix	2002:c0a8:0000::/48

Subnet calculation of IP 192.168.0.1

Subnet mask	Subnet bits	Mask Bits	Hosts per subnet	Host Address range	Broadcast Address
255.255.255.192	2	26	62	192.168.0.1 – 192.168.0.62	192.168.0.63

Subnet bits	Maximum subnets	Mask Bits	Hosts per subnet	Host Address range	Broadcast Address
8	256	16	65534	10.0.0.1 – 10.0.255.254	10.0.255.255

The transfer and reception of the data packets within the network the server should have knowledge about the data which is to be transferred and the address where the data is to be transferred. The computers in the network are identified by the MAC address and the IP addresses. The ARP or the Address Resolution protocol is used for the connection of the MAC address to the IP of the machines and this helps in the connection of the systems within the network.

The ARP Cache is also known as the ARP table. The ARP table is used to save the IP/MAC addresses in devices like switches and router. Once the devices in the network gets connected to the router, those IP addresses will be stored in cache memory, which is nothing but the ARP table. When a request is sent from a device for transferring the ARP table checks for the IP address connected to it and get the information convert it to packets and deliver them to the corresponding IP address. Hence, this reduces the waiting time during the transmission of management in a network and the efficiency of the network increase as a result.

IP subnetting calculation

The report is used for the description of the network layout and configuration of the network topology of the organization. It has been given that the organization is looking to expand their business procedures and the network would be distributed in six different sub networks. The company have also provide requirement about the use of IP addressing mode for the sub netting of the network. I as the Solution Architect is assigned with the responsibility of performing the task that would help the organization in implementing the required network architecture.

The description and calculations regarding the network topology are provided in this report.

This report contains the network topology and the justification of the network topology. In addition to this, the explanations about the number of hosts have also been provided in this report.

Figure 1: Network Diagram

(Source: created by author)

The network has been successfully divided into six different branches by using the sub netting method. The network contains a network that is divided by six different routers in which the connections are done according to the descriptions provided below:

The router in the Head Office and the Marketing Department are connected to the router of the Finance department. In addition to this, the Research and development router is connected to the routers of the IT Call Centre and router in the Information Technology. Additionally, the Finance Department router and the R and D router are connected with each other. This divides the network successfully however the employees in the network would be interact with each other without any barriers and the network efficiency would be maintained without too much congestion in the network.

The following requirements have been provided by the organization about the restructuring and expansion of their network:

Total number of machines to be allocated in the network: 1200 computers approximately.

Number of braches the network is to be sub netted to: 6

The number if machines to be allocated to the sic buildings approximately:

Finance Office – 260 workstations

IT Call Centre – 520 workstations

Research and Development Office – 120 workstations

Marketing Department – 40 workstations

Information technology – 130 workstations

Head Office – 60 workstations

Subnet Name	Needed Size	Allocated Size	Mask	Dec Mask	Address	Assignable Range	Broadcast
Head_Office	60	62	/26	255.255.255.192	10.0.7.128	10.0.7.129 – 10.0.7.190	10.0.7.191
Finance_office	260	510	/23	255.255.254.0	10.0.4.0	10.0.4.1 – 10.0.5.254	10.0.5.255
IT_Call Centre	520	1022	/22	255.255.252.0	10.0.0.0	10.0.0.1 – 10.0.3.254	10.0.3.255
Research_and_Development_Office	120	126	/25	255.255.255.128	10.0.7.0	10.0.7.1 – 10.0.7.126	10.0.7.127
Marketing_Department	40	62	/26	255.255.255.192	10.0.7.192	10.0.7.193 – 10.0.7.254	10.0.7.255
Information_Technology	130	254	/24	255.255.255.0	10.0.6.0	10.0.6.1 – 10.0.6.254	10.0.6.255

The system is configured with the 10.0.0.0/21 addresses. For the IP address 10.0.0.0/21 2046 number of IP address are available and among them 1130 are required, but 2036 addresses are allocated in the subnet. This helps us in minimization of the number of IP that are wasted in this network configuration.

ARP cache

If the number of hosts increases to a number more than 1024 then there might arise a case of the calculation of the network setup has to be altered in order to allocate more machines to the system. The configuration of the network would be have to be set up from scratch, and hence and a new system have to be used for the calculation of the subnet of the network. The configurations in the in the router interfaces have to be deleted and the some other network other than /21 sub netting system.

Subnet Name	Needed Size	Allocated Size	Address	Mask	Dec Mask	Assignable Range	Broadcast
Finance_office	1024	2046	10.0.0.0	/21	255.255.248.0	10.0.0.1 – 10.0.7.254	10.0.7.255
Head_Office	1024	2046	10.0.8.0	/21	255.255.248.0	10.0.8.1 – 10.0.15.254	10.0.15.255
IT_Call Centre	1024	2046	10.0.16.0	/21	255.255.248.0	10.0.16.1 – 10.0.23.254	10.0.23.255
Information_Technology	1024	2046	10.0.24.0	/21	255.255.248.0	10.0.24.1 – 10.0.31.254	10.0.31.255
Marketing_Department	1024	2046	10.0.32.0	/21	255.255.248.0	10.0.32.1 – 10.0.39.254	10.0.39.255
Research_and_Development_Office	1024	2046	10.0.40.0	/21	255.255.248.0	10.0.40.1 – 10.0.47.254	10.0.47.255

 

Conclusion

For conclusion it can be said that the network topology has been designed according to the requirement of the organization. The report provides the justification about the network topology. In addition to this, calculation regarding the IP of different machines have been provided in the report. The /21 routing system has been used for the assignment of IP to the network. However if the number machines increase in the system the calculation and the router configuration details would require to be changed. The supporting calculation and proper justification has also been provided in the report. Hence, it can be said that the network architecture for the organization has been defined efficiently in the report, however the calculation are limited for the /21 network whereas any increase the number of systems in the network would call for a redesigning of the network.

References

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