Saturday, September 10, 2016

IP Addresses

The networking devices need IP addresses to communicate with each other on the network. There are two types of IP addresses versions: IP Version 4 (IPv4) and IP Version 6 (IPv6).

IPv4 Address

                   In IPv4 address, the host can communicate in one of three different ways:

    Unicast: The process of sending a packet from one host to an individual host

   Broadcast: The process of sending a packet from one host to all hosts in the network

   Multicast: The process of sending a packet form one host to selected group of hosts

                   There are three types of addresses in IPv4 network range.
   Network address: A special network that refers to the network

   Broadcast address: A special address used to send data to the all hosts in the network

   Host address: The unicast address assigned to the end device in the network

Subnet Mask
                   The subnet mask is a 32-bit values used with IPv4 address that specifies the network portion of the address to the network device. The subnet mask uses 1s and 0s to indicate which bits of the IPv4 address are network bits and which bits are hosts bits.




For Example,
     Network             Network Address      Subnet Mask             Host Range                       Broadcast Address
192.168.1.0/24            192.168.1.0         255.255.255.0           192.168.1.1 to 254                     192.168.1.255
192.168.2.0/25            192.168.2.0       255.255.255.128         192.168.2.1 to 126                    192.168.2.127

IPv4 Network Classes
Address Classes           
First Octet Range
Prefix and Mask
Number of Possible Networks
Number of Hosts Network
A
1 to 127
/8    255.0.0.0
126 (27)
16,777,217  (224 – 2)
B
128 to 191
/16   255.255.0.0
16,382  (214)
65,534  (216 – 2)
C
192 to 223
/24   255.255.255.0
2,097,159 (221)
254 (28 – 2)

IPv4 Public and Private Addresses

                              Although most IPv4 addresses are public addresses designated for use in networks that are accessible on the Internet, there are blocks of addresses used in network that are not accessible on the Internet. These addresses are called private addresses.

The private address blocks are:

    Class A       10.0.0.0/8            (10.0.0.0 to 10.255.255.255)

   Class B       172.16.0.0/12      (172.16.0.0 to 172.31.255.255)

   Class C      192.168.0.0/16      (192.168.0.0 to 192.168.255.255)

Multicast Addresses

                          The multicast transmission is designed to conserve the bandwidth of IPv4 network. It reduces the traffic by allowing a host to send a single packet to a selected set of hosts. To reach multiple destination hosts using unicast communication, a source host would need to send an individual packet addressed to each host. With multicast, the source host can send a single packet that can reach thousands of destination hosts.  The address block is 224.0.0.0/4 (224.0.0.0 to 239.255.255.255).

Experimental Addresses

                            These addresses are reserved for future use. This suggests that they could be converted to usable addresses. Currently, these addresses are not usable in IPv4 network. However, these addresses are used for research. The address block is 240.0.0.0/4 (240.0.0.0 to 255.255.255.254).


 Default Route

                            The default route is “catch all” route to route packets when the specific route is not available. The default route address block is 0.0.0.0/8 (0.0.0.0 to 0.255.255.255).

Loopback

                            The loopback address is special address that hosts use to direct traffic to themselves. The address block is 127.0.0.0/8 (127.0.0.0 to 127.255.255.255).

Link-Local Addresses

                           These link-local addresses can be automatically assigned to the local host by the operating system in environment where no IP configuration is available. The address block is 169.254.0.0/16 (169.254.0.0 to 169.254.255.255).

Test-Net Addresses

                           The test-net-addresses are set aside for teaching and learning purpose. The address block is 192.0.2.0/24 (192.0.2.0 to 192.0.2.255).

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