What is IP, Subnet-Mask ,Subnetting and CIDR

What is IP(internet protocol) :

An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing.

IPv4:-  

Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number.^[2] However, because of the growth of the Internet and the depletion of available IPv4 addresses, a new version of IP (IPv6), using 128 bits for the IP address, was developed in 1995,^[3] and standardized in December 1998.^[4] In July 2017, a final definition of the protocol was published.^[5] IPv6 deployment has been ongoing since the mid-2000s.

 IP addresses are usually written and displayed in human-readable notations, such as 172.16.254.1 in IPv4, and 2001:db8:0:1234:0:567:8:1 in IPv6. The size of the routing prefix of the address is designated in CIDR notation by suffixing the address with the number of significant bits, e.g., 192.168.1.15/24, which is equivalent to the historically used subnet mask 255.255.255.0

The IP address space is managed globally by the Internet Assigned Numbers Authority (IANA), and by five regional Internet registries (RIRs) responsible in their designated territories for assignment to end users and local Internet registries, such as Internet service providers. IPv4 addresses have been distributed by IANA to the RIRs in blocks of approximately 16.8 million addresses each. Each ISP or private network administrator assigns an IP address to each device connected to its network. Such assignments may be on a static (fixed or permanent) or dynamic basis, depending on its software and practices.

Function:-

An IP address serves two principal functions. It identifies the host, or more specifically its network interface, and it provides the location of the host in the network, and thus the capability of establishing a path to that host. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."^[2] The header of each IP packet contains the IP address of the sending host, and that of the destination host.

 SUBNETTING:-

                                      The subnetting is used for to redused amount of wasting ip address.in networking , lets take a example that is we need 20 ip address then we will take a network there is 32 ip address then our 12 ip is waiste  .so the networking team found a solution of saving ip address that is subnetting ,not all waisted of ip sve but more of them can save now.

 Benefit of Subnetting :   
                                         

Reduced network trafic:-          One network will not access the data of other network without the use of router. Thus we can reduce the amount of data remain in one network. Less data less overhead, collision, or broadcast storm.

Simplified management :-     It's easier to identify and isolate network problems in a group of Smaller connected networks than within one gigantic network. Facilitated spanning of large geographical distances Because WAN links are significantly slower and more expensive than LAN links, a single large network that spans long distances can create problems in every area earlier listed. Connecting multiple smaller networks makes the system more efficient.

 

 Subnet mask :

                             A subnet mask is a 32-bit value that allows the receiver of IP packets to distinguish the network ID portion of the IP address from the host ID portion of the IP address. Every IP address is composed of a network component and a host component. The subnet mask has a single purpose: to identify which part of an IP address is the network component and which part is the host component. Subnet mask value 0 represent host ID while subnet mask value     1 to 255 represents Network ID in ip address.

NOTE:-We can also say that subnet mask is used to define the no. of host bit and no. of  network bit in network ip.

 

 Classless Inter-Domain Routing (CIDR) :

                                                                                                                                        This slash          ( / ) notation is sometimes called CIDR (Classless Inter-Domain Routing) notation. It's basically the method that ISPs (Internet service providers) use to allocate a number of Addresses to a company, a home—a customer. The slash notation is simply the number of 1s in a row in the subnet mask. The real reason to use CIDR notation is simply that it is easier to say and especially to type.

 

Block Size :

The process of subnetting creates several smaller classless subnets out of one larger classful . The spacing between these subnets, or how many IP addresses apart they are, is called the Block Size.

Network ID and Broadcast ID :

                                                                        The first address in a network number is called the network address, or wire number. This address is used to uniquely identify one segment or broadcast domain from all the other segments in the network.

The Broadcast ID :     
                                       The last address in the network number is called the directed broadcast address and is used to represent all hosts on this network segment. it is the common address of all hosts on that Network ID. This should not be confused with a full IP broadcast to the address of 255.255.255.255, which hits every IP host that can hear it; the Broadcast ID hits only hosts on a common subnet. A directed broadcast is similar to a local broadcast.

The main difference is that routers will not propagate local broadcasts between segments, but they will, by default, propagate directed broadcasts

 Host Addresses :

                      Any address between the network address and the directed broadcast address is called a host   address for the segment. You assign these middle addresses to host devices on the segment, such as PCs, servers, routers, and switches.