Transport Layer, IP Addressing, CSMA/CD Scheme, And Wi-Fi Security Are Essential Topics In The Essay.

Question 1 Transport Layer

a) As we have seen, the Internet layer of TCP/IP has two protocols – IPv4 and IPv6. The transport layer provides two main protocols TCP and UDP (along with some special-purpose, minor protocols). But these are for very different reasons. Why are the Internet and Transport layers very different in providing two protocols?

b) Since UDP does very little that is different from IP, why do we even have a transport layer such as UDP?

c) Describe how DDoS attacks may be mounted against TCP and UDP service . In what way will being connection oriented be different for TCP and UDP?

Question 2 – IP Addressing

a) Perform the following boolean operations on the given bit patterns 

i. not 11100010
ii. 11100010 or 00001110
iii. 11100010 and 00001110

b) What are the subnet masks for the following slash address blocks?
i. 9
ii. 17
iii.31

c) Are the following address masks legal? If so, what are their slash forms? If not, why are they not legal?
i. 255.255.248.0
ii. 255.224.252.0
iii. 255.255.255.224
iv. 255.255.156.0

d) How many computers are in networks with the following address blocks?
i.13
ii. 26

e) A small company is assigned the class C network 205.67.35.0. You need to divide this network to provide subnets for three departments using fixed-length subnetting. The departments are approximately the same size. Show the network and broadcast addresses for each subnet. Show the slash notation. How many hosts are on each subnet? Are the resulting subnets class C networks? 

Transport layer

The transport layer of the TCP/IP appear, the data transmission is done using UDP and TCP. In the present years, Stream Control Transmission Protocol (SCTP) is introduced for transmitting the data stream and the data residing in the transport layer can be broken into different segments and transmitted to the host using the network layer. The data transferred using the transport layer are isolated into segments and sent using the network layer. The parts are also broken into datagram and switch over the web. The objective PC where the data is sent needs to sit tight for the datagram to get in touch with them, they are accumulated to shape the section, and the vehicle is done.

The internet and the transport layer differs from each other because both the layers uses different protocol for data communication and both have different functionality. The datagram received from a network layer is broken down into small chunks and is forwarded to the Ethernet frames.  The UDP protocol of the transport layer uses the datagram size, checksum from the IP address and transmission of the data packets in the network.

In case of multiplex services the port number used in the UDP protocol is essential for differentiating the services arriving from different point in the network or from the same host address. Using the IP address it is not possible to differentiate the service for the different hosts communicating with each other in the network. When a packet reaches the destination address the packet is required to be used by a specific application running on the host. A de multiplexing logic is required for identification of the packets and which application is required to use the data packets determining the port address. The port information can be fetched using the UDP protocol and IP uses the port address for delivering the packet to the destination application.

The DDoS attack is defined as distributed denial of service and this can compromise multiple system and the main victims of the DDoS are the target and the systems used for reaching the target. Many sources can be involved for the DDoS attack and multiple computers and internet connection are used for the attack. For the DDoS attacks both the TCP and UDP connections can be used and use of the connection depends on the hacker using the path for flooding the system. The UDP connection consumes less network resource because it uses a three way handshake protocol. The hackers can use the TCP connection to send an incomplete HTTP request that causes the server not to time out and thus the hacker have the time for flooding the server with numerous number of request. For DDoS attack using UDP the hacker enters the system by selecting a random port from a remote host and check the response of the host. If the application responds the port number is used for attack.

1. Boolean Operation
2. not 11100010

= 00011101

1. 1110 0010 or 00001110

OR Result

11100010 and 00001110

AND Result

1. Subnet calculation
2. /9 = 255.128.0.0
3. /17= 255.255.128.0
4. /31= 255.255.255.254

1. Address mask
2. 255.255.248.0= /21
3. 255.224.252.0=

1111111.11100000.11111100.00000000

It is not a lawful subnet due to the fact that a subnet cover is required to be loaded with 1 from the left hand side. Thus the option documentation is required to be utilized and with/x and the x is portrayed as the quantity of 1 bits. It likewise indicates the bits from the left hand side that can be utilized for the recognizable proof of the system and the bits that can be overlooked levy to their distinction from each of the hub in the subnet.

255. 255.255.255.224= /27
256. 255.255.156.0= it is also an illegal subnet.
257. 11111111. 11111111. 10011100

IP Addressing

A valid Prefix for 4 bit wide net is /28 (32-4) with subnet mask 255.255.255.240 only. It results in 11111111 11111111 11111111 11110000.

1. Address Blocks
2. /13= 524286
3. /26= 62
4. Network and Broadcast Address

All the IPs are in class c network

The collision cannot be detected by analyzing the power level of the medium and the measurement of the power level of the RF medium is not possible. If the collision cannot be detected then the collision cannot be avoided. The detection of the collision in a network helps to avoid it and give better performance. The CSMA/CD is used to check the collision in the network and transmit the data packets in the network according to the collision detected in the system. If a collision is detected in the network the device sending the data packets have to wait for a random time for receiving the acknowledgement and the end device would also have to wait for receiving the data packets. This process works for the wired network but in case of the wireless networks there is no possible methods for the detection of collision in the network and thus the sender and the receiver can send and receive data packets but cannot sense the medium used for the transmission of the data packets. Thus for avoiding the collision in the wireless medium the CSMA/CA is used that consists of some control messages for avoiding the collision in the network and decrease the waiting time.

The scope of the wifi get to point is 15m though the extent of the room is 60 by 40 meter in measurement. If a get to point on channel 1 is transmitting, all the adjoining customers and the get to point with a similar divert would bring about postponement in the transmission. The result is that throughput is inimically affected. Near to get to focuses and clients need to hold up any more drawn out to transmit in light of the way that they have to continue. The futile medium question overhead that occurs in light of the fact that all the get to focuses are on a comparable channel is called co-channel impedance (CCI). The settled channel portion can be swapped by unique channel assignment for settling the issue confronted by the staffs confronted in the stock.

The wireless access point is required to be reconfigured and security encryption is required to be applied that would restrict the unauthorized to access the network. Currently the WPA2 PSK is required to be used for creation of an encryption key. The password used as the encryption is required to be a combination of text, special character and numerical such that it is secured from brute force attack. The organization have the requirement of secure the wireless network with a strong encryption algorithm. The unauthorized access of the wireless network can lead to a risk for the data loss and hacking of the organizational information causing a huge loss for the company. The customer records can be stolen for illegal use and different security rules is required to be applied for securing the network. The password for the wireless device should be changed frequently such that the password cannot be breached.

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