Tips and Tricks of Networking

Subnetting:

The technique of dividing a network into logical subnetworks or subnets to avoid network traffic is called subnetting.This can also be stated as splitting a single IP address into many subnetwork addresses. It allows you to manage distinct network under a single class address. This can be done by shifting bits from the Host IDs to the network ID. Subnetting allows you to more networks with fewer hosts because network ID. In this way, you can connect to the Internet with the single shared network address. In subnetting, network IDs are merged with the host ID bits or few of the Host IDs that are used as subnets. According to the standard IP address classes, there are only three possible network ID sizes: 8-bits for class A, 16-bits for class B and 24-bits for class C. subnetting allows you to use the limited space of an IP address efficiently.

SUBNETTING CAN BE PERMORMING IN TWO WAYS:
A) Fixed length subnet mask (FLSM)
B) Variable length subnet mask (VLSM)

Subnets:
A network that exists within the class A, B or C network is called a subnet. It can also be defined as a network within a network. Subnets are created to extend network IDs by using one or more class A, B and C addresses. Therefore, subnets can have a network ID of any length. All devices that have IP addresses with same prefix are defined as subnets. These are connected to the Internet by using the same shared network. While designing a subnet, always specify the maximum number of subnets that are required, and ensure that enough host addresses are available.

Supernetting:
Supernetting is defined as the combination of all network routing commands in a single routing table entry. It is commonly called Classless Inter-Domain Routing (CIDR). It is designed to solve the problems such as, wastage of many addresses in the class addresses described by the classful address. Supernetting resolves many problems arising because of subnetting, such as, all zeroes, and all ones marks in the IP addresses. Like subnetting, can take any number of host IDs. The difference between supernetting, the host and network IDs are merged, while in subnetting the IDs are split. The CIDR masks for classes A, B and C are /8, /16 and /24.

CIDR value:

/8= 255.0.0.0                                      /9=255.128.0.0

/10=255.192.0.0                                 /11=255.224.0.0

/12=255.240.0.0                                 /13=255.248.0.0

/14=255.252.0.0                                 /15=255.254.0.0

/16=255.255.0.0                                 /17=255.255.128.0

/18=255.255.192.0                             /19=255.255.224.0

/20=255.255.240.0                             /21=255.255.248.0

/22=255.255.252.0                             /23=255.255.254.0

/24=255.255.255.0                             /25=255.255.255.128

/26=255.255.255.192                         /27=255.255.255.224

/28=255.255.255.240                         /29=255.255.255.248

/30=255.255.255.252                         /31=255.255.255.254

/32=255.255.255.255

For example:

IP Address =       10.1.1.1/14

Subnet mask =     255.252.0.0

IP Address =       172.16.1.1/20

Subnet mask =    255.255.240.0

IP Address =       192.168.10.1/26

Subnet mask =    255.255.255.192    

and so on...

to be continued......................