Understanding IP Address Ranges, Subnetting, And NAT

1. IP Addressing
a) Classical IP addressing provided three address classes for assigning to network
devices (hosts). How can you determine which class an IP address belongs to by
looking at the first octet?
b) Windows and other operating systems allow a host to have multiple IP addresses. What purposes are served by assigning a host multiple IP addresses? Will this have any consequences for the ARP protocol?

2. Subnetting
a) You are provided with the address range 192.168.10.0/24. Create a sub?networking scheme that provides six networks in this range.
b) What subnetting alternatives exist for providing a network address for a point?to?point link?

3. Practice Exam Question
What is the difference between NAT and PAT? Reflection Exercise:

Reflection is the process of self?evaluation of your learning experience. It guides you in critically
evaluating your progress in mastering a concept or technique.
a) Write a paragraph that summarises what you have learned from third two modules
b) Briefly describe what concepts from these modules you don't yet fully understand

IP Address Ranges and Class

a) Classical IP addressing provided three address classes for assigning to network devices (hosts). How can you determine which class an IP address class by checking its first octet? 

By checking the first octet of an IP address, one can be in a position to identify the class of the IP address. For instance, the octet range of Class A is 1 – 126, the octet range of Class B is 128 – 191 and the octet range of Class C is 192 – 223 (Golan, Rivner, Tsur, Orad, & Bennett, 2015).

b) Windows and other operating systems allow a host to have multiple IP addresses. 

What is the function of multiple IP addresses in a host? Will this have any 
consequences for the ARP protocol? 
1 Mark 

There are many functions that a host serves by having multiple IP addresses. For instance, a computer connected to a host that is down can add its address to another host that is much faster this will enable him access faster internet connectivity. Sometimes one may be blacklisted as SPAM (Stolorz et al, 2015). Using multiple IP addresses makes one escape being blacklisted as a SPAM. Sometimes one my need to host many SSL site, using multiple IP addresses helps one do so much easier. One may be having a need to use an IP address that will be transferred to another host sometimes later. The use of multiple IP addresses can help him achieve this much easier. Additionally, someone might need to run the same service multiple times, thus the use of multiple addresses is of much help. Sometime you find some services having similar port number. Therefore, for these services to run you need to have many IP addresses on one server (Shang, Droms, & Zhang, (2016).

Multiple IP addressing has no consequences to the ARP protocol.

a) you are provided with the address range 192.168.10.0/24. Create a sub-networking 

scheme that provides six networks.

Address 192.168.10.0 = 11000000.10101000.00001010.00000000

Default class C Subnet = 255.255.255.0 = 11111111.11111111.11111111.00000000

To create the network we have 8 bit available.

We use the following formula to calculate the needed bits.

(2^x)-2 >= subnets

Example (2^3)-2 =6 (the number of requested networks)

we create the subnet mask using 3 bits => 128+64+32 = 224.

224 is equivalent to = 11111111.11111111.11111111.11100000

Below are the sub-networks. They are obtained by replacing the first three digits in last octet.

Subnet 0   = 11000000.10101000.00001010.00000000 = 192.168.10.0
Subnet 1  =  11000000.10101000.00001010.00100000 = 192.168.10.32
Subnet 2  = 11000000.10101000.00001010.00100000 = 192.168.10.62
Subnet 3  = 11000000.10101000.00001010.01100000 = 192.168. 10.96
Subnet 4   = 11000000.10101000.00001010.10000000 = 192.168. 10.128
Subnet 5 = 11000000.10101000.00001010.10100000 = 192.168. 10.160
Subnet 6   = 11000000.10101000.00001010.11000000 = 192.168. 10.192
Subnet 7  = 11000000.10101000.00001010.11100000 = 192.168. 10.224

Functions of Multiple IP Addresses

b) What subnetting alternatives exist for providing a network address for a point?to?point link? 

There exists two ways of providing address for point to point. These are numbered and unnumbered connection (Vardy, 2016). A numbered connection has a unique IP address in every interface while the unnumbered connection uses no IP address in connection.

NAT (Network Address Translation) is a mode of translation that does translation one-on-one i.e. from one IP Address to another IP Address. This mostly done by organizations that need  internal internet access using a one public IP address which translate into one IP in private space (Carter, McClain, Allen, Olds, & Burch, 2015). A good example is when a server with IP addresses 10.1.2.324(which cannot be routed in the internet) in a company. If the company needs to publish the webpage on the server to the internet, it may use the internet routable address 33.3.2.3 for this server. Thus, the one-on-one relationship between the two addresses (John, Al-Shalash, & Xiang, 2016).

In consideration of the NAT situation, a table will be as shown

Internal IP  Internet IP

10.1.3.25  33.3.2.25

10.1.3.26  33.3.2.26

10.1.3.27  33.3.2.27

On the other hand, in Port Address Translation (PAT) the relationship is many-to-one. This one is mostly applied on firewalls when all IP addresses are required to use a single IP address (Carter et al, 2015). For instance, when all computers are required to show the same IP addresses when browsing the internet. The PAT is set up by the firewall making it achievable. Considering a company that has 100 computers operating on network 192.168.2.0/24 with the public address of 24.30.11.10 the firewall will do the configurations so that all the computers will browse with the address 24.30.11.10 all the computers will have different port numbers in every session, but have same IP address. A PAT table is displayed below.

Internal IP Internet IP Port

192.168.2.10 24.30.11.10 5005

192.168.2.11 24.30.11.10 5006

192.168.2.12 24.30.11.10 5007

192.168.2.13 24.30.11.10 5008

a) Write a paragraph that summaries what you have learned from third two modules 

In the previous third two modules, we discussed to how to configure a switch at a basic level. This is configuring a switch and doing network verification from the end devices. I also learned differentiating broadcast and unicast traffic. What we discussed basically in switch configuration is the naming of a switch, setting time and finally adding a message of the day to the switch. To achieve this, we set up a packet tracer with switches, connect the work station using straight through cables because they are different devices and connect the switches with crossover cables because they are similar devices. To get started on switch configuration, we go to command prompt and enable admin level by typing enable on the ‘CLI’. We first configure the terminal by typing configure terminal. The switch is now set to in configuration mode. Here we can name the switch by typing command hostname then the name of the switch. Now the name of the switch changes to what you named it e.g. First(config)# from the initial name i.e. Switch(config)#. Setting up time is the most important thing. We use the command First(config)# clock time zone AWST 8 0. The final thing is now entering the message of the day. We write the command First(config)# Text message. You should end with } as a finishing character. This is how the switch is set up for the basic level.

Creating Subnets with IP Addresses

The next module we discussed the differences between broadcast and unicast packets and understanding of collision domains and its effect on the network. Unicast is the transmission of packets to a single recipient while multicast refers to transmission of IP packets to multiple recipients. On the other hand collision domain refers to some part of a network that is being shared and where data may collide with another as it is being sent. The shared mediums may be repeaters such as hubs.  A collision is said to occur when a node determines that that collision has taken place and in this case, a protocol of recovery from this is required. To learn this, we looked at different configurations of two hubs, a hub and a switch and two switches. We observed that hubs are prone to collision because they don’t have memory for storing packets, therefore packets are transmitted as they are received. This makes the hub to work in half-duplex because it can only work in one direction at a moment. This makes them have a higher collision than repeaters and switches. Switches were observed to have no collision because they have many collision domains. Every port is connected to another during communication and thus every link possesses a collision domain which reduces any possible collision. But in case any occurs, there is some memory that enables re-sending of the packets lost.

b) Briefly describe what concepts from these modules you don't yet fully understand

Why collision still exists when a hub and a switch are connected together and a switch has multiple collision domains that can prevent packets collision. I also find it hard to verify network connectivity from end devices when configuring a switch.

References

Carter, S. R., McClain, C. B., Allen, J. P., Olds, D. R., & Burch, L. L. (2015). U.S. Patent No. 9,122,533. Washington,  DC: U.S. Patent and Trademark Office.

Golan, L., Rivner, N., Tsur, M., Orad, A., & Bennett, N. (2015). U.S. Patent No. 9,076,132. Washington, DC: U.S. Patent and Trademark Office.

John, K. M., Al-Shalash, M., & Xiang, Z. (2016). U.S. Patent No. 9,451,643. Washington, DC: U.S. Patent and Trademark Office.

Shang, W., Yu, Y., Droms, R., & Zhang, L. (2016). Challenges in IoT networking via TCP/IP architecture. TechnicalReport NDN-0038. NDN Project.

Stolorz, P. E., Salmon, J. K., Warren, M. S., Koller, J. G., Hagberg, A., Yevmenkin, M., ... & Middleton, T. (2015). U.S. Patent No. 9,203,636. Washington, DC: U.S. Patent and Trademark Office.

Vardy, A. (2016). Subnetting For Beginners: How To Easily Master IP Subnetting And Binary Math To Pass Your CCNA-CCNA, Networking, IT Security, ITSM. CreateSpace Independent Publishing Platform.