Analyzing TCP/IP, IPv4, Network Structure and Identification

This assignment solution addresses key concepts in computer networks, focusing on the TCP/IP protocol suite and IPv4 addressing. The solution begins by outlining the three primary tasks handled by the internet layer, including data unit transmission, packet rearrangement, and error detection. It then describes the IPv4 header length field, explaining its variable nature and purpose in notifying the packet processor. The solution also details the IPv4 Identification field, explaining its role in detecting and removing duplicate datagrams, along with its use as a diagnostic tool. Furthermore, the assignment classifies given IP addresses (227.12.14.87 and 14.23.120.8), identifying them as Class D and Class A, respectively, and describing their typical uses. Finally, the solution identifies and describes the networks and routers in a provided network diagram, highlighting the connections between Ethernet LANs and point-to-point WANs. The solution references several sources to support the discussed concepts.

Question1: [3mks]
Describe the three primary tasks handled in the internet layer by TCP/IP
The internet layer is responsible for transmitting data from the source to the final destination
since accepts these data from the transport layer taking them to the network interface layer
(Farhady, Lee and Nakao, 2015). The following are some of the tasks that it performs during its
function.
a. It helps in the transmission of data units that are packed to a single unit and sent to the
link-layer which is normally found on the link that the host is connected to directly. This
process happens to outgoing packets.
b. It captures data packets that are being sent to another system and rearrange them as
required so that information being passed is not lost. This means that it will look for the
shortest path possible in the case of alternative paths existing and direct the packets
containing information to that path.
c. It detects errors that normally occur during packet transmission within a network.
Question2:[4mks]
Describe the IPv4 Header Length field.
IPv4 header length is a variable since it allows options of IP. By default, it contains a value of 5
which can be estimated to be 160 bits or 20 bytes (Rennie and Morrison, 2013). And the
maximum value contained is 15 estimated to be 480bits or 60 bytes The header length is used in
notifying the packet processor the number of 32-bit words contained in the header.
What is the purpose of the Identification field in IPv4?
IPv4 Identification field is a unique value that consists of 16-bit and it is there in every datagram
existing in a given source and its destination addresses together with the protocols. The ID is not
repeated within a certain lifetime of the datagram.
The purpose of having ID in IPv4 are as follows:

a. The field is normally used as a way of detecting and removing duplicated datagrams from
a network whose routers are said to be congested.
b. The field is used as a diagnostic tool that looks at various datagrams being measured
along with a network in different locations.
c. In some cases, it used to reduce duplication that might occur on other layer protocols that
are higher.
Question 3:[2mks]
Classes of the IP address given below and a brief description
227.12.14.87
This address is class D since the first byte of its address is 227 and we know that in class D the
first byte starts from 224 to 239. These addresses are used for multicasting (Zhang et al., 2014).
14.23.120.8
This address is class A since the first byte of its address is 14 and we know that in class A the
first byte starts from 0 to 127. In this class, the first eight bits represent the network while the
remaining 24 bits represent the host. This class can be used in assigning devices to application
sites that require many people to join (Scherer and Sholtis, 2015).
Question 4:[6mks]
Identifying each ‘Network’ and ‘Router’ in the network shown below.
There are eight networks: N1 to N8
There are eight routers: R1 to R8
N1 to N6 are Ethernet LANs

N7 and N8 are point-to-point WANS
Below is how they are connected in the network
R1 connects N1 and N2
R2 connects N1 and N7
R3 connects N2 and N8
R4 connects N7 and N6
R5 connects N6 and N3
R6 connects N6 and N4
R7 connects N6 and N5
R8 connects N8 and N5

The figure above shows how each route is placed within each network when transmitting
information from one point to another. It shows how N8 and N7 which are wide area network
connects to other local area networks. In this figure N6, N3, N5 and N4 are on one side together
with R4, R8, R6, R7 and R5 connected to N2 and N1 together with its routers via the two
N1
N2
N7
N8
N6 N4
N5
N3
R2 R4
R1
R3 R8
R7
R5
R6

networks N8 and N7. From this indication, one can now troubleshoot the errors that may arise
physically on each network and routers (Xylomenos et al.,2013).
You can even go further and calculate for subnets depending on switches and devices that have
been set in each network and know which network works best. One can also look for alternatives
routes that might be considered when transmitting information after the networks and routers
have been labeled appropriately as shown above.

Reference
Farhady, H., Lee, H. and Nakao, A., 2015. Software-defined networking: A survey. Computer
Networks, 81, pp.79-95.
Rennie, F. and Morrison, T., 2013. E-learning and social networking handbook: Resources for
higher education. Routledge.
Scherer, C.B. and Sholtis, J.K., Mertek Industries LLC, 2015. Networking cable tracer system.
U.S. Patent 9,196,975.
Xylomenos, G., Ververidis, C.N., Siris, V.A., Fotiou, N., Tsilopoulos, C., Vasilakos, X.,
Katsaros, K.V. and Polyzos, G.C., 2013. A survey of information-centric networking
research. IEEE Communications Surveys & Tutorials, 16(2), pp.1024-1049.
Zhang, L., Afanasyev, A., Burke, J., Jacobson, V., Crowley, P., Papadopoulos, C., Wang, L. and
Zhang, B., 2014. Named data networking. ACM SIGCOMM Computer Communication
Review, 44(3), pp.66-73.