Advantages Of Using Subnetting

Subnetting is allowed you to divide one physical network which is whether a class A, B, or C into several smaller logical subnetworks. The main idea of subnetting is borrowing bits from the host IP address and using them to create one or more networks within the network. Furthermore, It permits using two or more local area networks (LANs) technology in the same network such as Ethernet and Toking ring (Cisco 2005; PSI 2000).

Advantages of using subnetting:

It is useful to control and to reduce the network traffic by limiting number of broadcasts.

It is allowed any organization to subnet its network without needed to have a new network IP through an internet service provider (ISP).

Subnetting was so helpful to solve the problem of lacking IP addresses on the Internet.

Allowing to use two or more LAN technologies together in the same network.

Subnets also helpful to minimize the size of the routing tables on the internet since additional network numbers will not being added to the table.

When you want to isolate segments for security reasons such as accounting and sales segment.

When you want to isolate bad segments such as domination hosts which use most of the LAN bandwidth (PSI 2000).

Disadvantage Advantages of using subnetting:

Subnetting decreases the total number of IP addresses in the network but may need buying additional hardware such as a router. So, it may cost lots of money(PSI 2000).

It cannot correct the lack of efficiency because companies still assign address block regarding to classes (Kozierok 2005).

Supernetting

It is the opposite of subnetting that is allowed you to divide one physical network into several smaller logical networks. On the other hand, Supernetting is allowed you to combine one or more smaller logical network to making one large network. It is a part of classless inter domain routing (CIDR) (Wright 1998). In addition, it is used in routing tables to merge nearby class C (Blank 2002). It is necessary when you need more hosts on the network. So, the main concept of supernetting is borrowed one or more bits from the current network address and using it to produce a large amount of hosts (Inetdaemon).

Private and Public IP addresses

Public IP Address

It is an IP address which is able to be seen by the public. Public IP Address allows people access your computer form everywhere and know about you such as a web server.

Private IP Addresses

It is used on a private network and it is not able to route through the public Internet. It is useful for security reasons. All privet IP addresses are fallen within the following IP address ranges (Syndication 2007):

Class A

10.0.0.0 through 10.255.255.255

Class B

172.16.0.0 through 172.31.255.255

Class C

192.168.0.0 through 192.168.255.255

2- Subnetting calculate :

192.168.1.40/24

IP class / class C

Total usable subnets/networks / 256

Total usable IP addresses in each subnets/networks / 254

The first 5 subnets/networks / 192.168.1.0, 192.168.1.1, 192.168.1.2, 192.168.1.3,

192.168.1.4

10.4.78.21/8

IP class / class A

Total usable subnets/ networks / 1677216

Total usable IP addresses in each subnet/network / 1677214

The first 5 subnets/networks / 10.0.0.0, 10.0.0.1, 10.0.0.2, 10.0.0.3, 10.0.0.4

10.0.0.9/24

IP class / class A

Total usable subnets/networks / 256

Total usable IP addresses in each subnets/networks / 254

The first 5 subnets/networks- 10.0.0.0, 10.0.0.1, 10.0.0.2, 10.0.0.3, 10.0.0.4

203.51.131.23/27

IP class / class C

Total usable subnets/ networks / 32

Total usable IP addresses in each subnets/networks /30

The first 5 subnets/networks-203.51.131.0, 203.51.131.1, 203.51.131.2, 203.51.131.3,

203.51.131.4

198.110.43.112/26

IP class / class C

Total usable subnets/ networks / 64

Total usable IP addresses in each subnets/networks / 62

The first 5 subnets/networks / 198.110.43.64, 198.110.43.65, 198.110.43.66, 198.110.43.67,198.110.43.68

3- Static and dynamic routing :

Static routing manually is configured into the routing table by configuration file or a network administrator who can access and configure the routers (Inetdaemon2). So, it is called static because it needs someone who can create that routing table physically. In addition, it provides control over routing (Balchunas 2007).

Advantages of Static Routing:

It reduces the physical hardware overhead.

It also minimize the bandwidth overhead (Balchunas 2007).

Disadvantages of Static Routing:

Static routing is a manual process so it will not work good with a massive number of routing.

It also does not fix any connection problem so the router must configured manually to solve any connection down (Inetdaemon2).

Difficult to configure large network (Balchunas 2007).

Dynamic routing

Dynamic routing automatically is configured by a routing protocol that runs on the routers (Balchunas 2007). Dynamic routing protocols are applications that can find a network destination and then record it into the routing table (Inetdaemon2).

Advantages of Dynamic Routing:

Easy to configure a big networks.

Dynamically change to a different route if there is any connection down (Balchunas 2007).

Disadvantages of Dynamic Routing:

Consuming more bandwidth.

It consumes more hardware as well.

It chooses the best connection way regarding to the routing protocol not to the routers administrator (Balchunas 2007).

Commonly used dynamic routing table

RIP (Routing Information Protocol).

EIGRP (Enhanced Interior Gateway Routing Protocol).

OSPF (Open Shortest Path First) (Balchunas 2007).

4- The difference between a layer 2 and a layer 3 network device

The difference between them is a layer 2 device works only with MAC addresses to forward network data packets; however a layer 3 device works on IP address. Moreover, layer 2 devices are transfer network packets from physical address to physical address but layer 3 devices looking for the best route to transmit data packets. So, layer 2 networks are faster than a layer 3 network because it just needs to forward data to the right destination without make any decision (Simon 2006).

Example of layer 2 device and describing it: Switch.

It is used to connect two local area networks (LAN) or more. It works under OSI (Open System Interconnection Reference) model Layer 2. Furthermore, It usually has multiple ports to connect devices together or to connect two or more local area networks (LAN). it receives data and forwards it depending on the destination MAC (Media Access Control) address to only destination that should receive it . Moreover, It only sends data within the same subnet as well (Maufer).

Example of layer 3 device and describing it: Router.

Router is used to connect two wide area networks (WAN). It works at OSI (Open System Interconnection Reference) model Layer 3. Furthermore, It forwards data depending on the destination network address to only destination that should receive it as well (Maufer).