IPV4 subnetting
Hey I know I know how should to learn subnetting or subnet mask that’s why i’m created this blog so don’t worry about that. ok let’s move to the topic.
Let’s go invent tomorrow rather than worrying about what happened yesterday. -steve jobs
First i assume you already know about networking fundamentals means: what is networking,OSI reference model,TCP/IP etc…
The Internet Protocol Version 4 is a 32-bit address. In ipv4 have four octets each octet contains eight bits.
The IPV4 Addressing system is divided into five classes of IP Addresses. All the five classes are identified by the first octet of IP Address.
IPV4 address classes A to C identify single hosts, and are called unicast addresses.
IPV4 addresses are usually represented in dot-decimal notation, consisting of four decimal numbers, each ranging from 0 to 255, separated by dots, e.g., 192.0.2.1. Each part represents a group of 8 bits of the address.
Types Of Classes a Range of five IP Addresses:-
CLASS-A:1–127, Default Subnet Mask of class A (255.0.0.0)/8.
CLASS-B: 128–191 →DSM (255.255.0.0)/16.
CLASS-C: 192–223 →DSM (255.255.255.0)/24.
CLASS-D: 224–239 →DSM (NOT APPLICABLE).
CLASS-E: 240–255 →DSM (NOT APPLICABLE).
NOTE: I’ll refer here to the default subnet mask →DSM, so don’t confuse what is DSM. 127 →(LOOPBACK) →It’s also class-A (DSM-255.0.0.0)/8.
CIDR:
CIDR (Classless Inter Domain Routing) is an alternate method of representing a subnet mask.It is simply a count of the number of network bits.in the subnet mask, The CIDR number is typically preceded by a slash “/” and follows the IP address.FOR example, an IP address of 192.168.0.0 with a subnet mask 255.255.255.0. (which has 24 network bits) would be represented as 192.168.0.0/24.
In subnet mask we are using two methods one is Fixed Length Subnet Mask(FLSM) and another one is Variable Length Subnet Mask (VLSM).
What is FLSM:-
FLSM is used to equally split the IP address to more than one office.Subnet mask is same for all the office. now let’s move to the example:
Here i purchased 215.30.10.0 class B IP address, Default subnet mask 255.255.0.0. 215.30.10.0 Divide this IP address into five networks.
step 1: Find default subnet mask →255.255.0.0.
step 2: Find Block Size →3 bits.
215.30.10.0 this IP is class B its CIDR notation /16. Because class B has two network bits and the remaining two host bits.
215.30. — — — — — — — — . — — — — — — — — . → 215.30.128 64 32 16 8 4 2 1.128 64 32 16 8 4 2 1. 128 64 32 16 8 4 2 1 is the value of each bits.2^n use this formula 2¹=2,2²=4,2³=8. my requirement is 5, which is a bigger number than five, but it’s okay. The reason for getting bigger than five is three bits. we need to use the formula 2^n when it comes to network and if we compute three bits from right to left as network then we get 32 block size.
step 3: Find New Subnet Mask(NSM) →255.255.224.0.(/19)
Add those three bit values(128+64+32) and you get 224.
step 4: Find Increment value →32.
step 5: Use Increment to find Network ranges.
215.30.10.0–215.30.10.31
215.30.10.32- 215.30.10.63
215.30.10.64–215.30.10.95
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Stay hungry, Stay foolish.- steve jobs
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HAPPY NETWORKING:)-
