netconnect.tar.gz

This course is a quick guide for understanding the internet protocol standard IPv4, including its packet structure, subnetting, and address configuration on hosts and routers. It also discusses the sixth version, IPv6, and its addressing scheme, subnetting, and coexistence with IPv4.

A Quick Guide for IP Subnetting

# Network mask and usable IP addresses
**IP subnetting** is a technique used by network admins or designers which allows the allocation of a certain number of IP addresses for certain networks to accomplish a specific goal. Before we start with IP subnetting, we must first answer the following questions.

1) How many IP addresses can we assign with a given mask? (for example, `/24`)
2) What are the first and last IP addresses for a given network address?
3) Which IP addresses from the network can be used?

# Examples
Let’s take the `192.168.0.0/24` network and answer the 3 questions:
 1) The maximum number of IP addresses from a network mask of `/24` is $256$ $(32 - 24 = 8,\space 2^8 = 256)$.

 2) First IP: `192.168.0.0`. Last IP: `192.168.0.255`.

 3) All of the IP addresses from `192.168.0.1` to `192.168.0.254` are usable in the network.


Thus, the `192.168.0.0/24` network contains the following IP addresses:

`192.168.0.1`, `192.168.0.2`, `192.168.0.3` ... `192.168.0.255`


>**NOTE**: Only $254$ IP addresses will be available from the $256$ because the first address (`192.168.0.0`, the network address) and the last address (`192.168.0.255`, the broadcast address) cannot be used. This is because these addresses have a clear purpose:
>1) **Network address** represents the whole network. In a telecommunications network, we have multiple hosts so a network address is used to identify the network.
>2) **Broadcast address** sends traffic or packets to all devices in the network.
>
>These addresses are part of the protocol and fixed so they cannot be assigned to the hosts.


Let’s take another example with the `10.222.24.0/24` network and answer the three questions:

1) The maximum number of IP addresses from a network mask of `/24` is $256$ $(32 - 24 = 8,\space 2^8 = 256).$
2) First IP: `10.222.24.0`. Last IP: `10.222.24.255` 
3) All of the IP addresses from `10.222.24.1` to `10.222.24.254` are usable in the network. The addresses `10.222.24.0` and `10.222.24.255` are not usable because they are network and broadcast addresses respectively.

 In this example, let’s take the `172.22.9.0/27` network and answer the three questions: 
1) The maximum number of IP addresses from a network mask of `/27` is $32$ $(32-27 = 5,\space 2^5 = 32).$
 2) First IP: `172.22.9.0`. Last IP: `172.22.9.31`.
 3) All of the IP addresses from `172.22.9.1` to `172.22.9.30` are usable in the network. The addresses `172.22.9.0` and `172.22.9.31` are not usable because they are network and broadcast addresses respectively.


The last example for this section is the `192.168.11.0/30` network: 

1) The maximum number of IP addresses from a network mask of `/30` is $4$ $(32 - 30 = 2, \space2^2 = 4).$
2) First IP: `192.168.11.0`. Last IP: `192.168.11.3`
3) All of the IP addresses from `192.168.11.1` to `192.168.11.2` are usable in the network. The addresses `192.168.11.0` and `192.168.11.3` are not usable because they are network and broadcast addresses respectively.





Learn to use a network address to determine the usable IP addresses.

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Prerequisites of IP Subnetting

Network mask and usable IP addresses