Introduction
Because subnet masks can get very confusing, the creators of this wonderful network technology also made available a few things to make life somewhat easier.
The following chart is really a summary of what we've seen so far. It gives you a good idea of the networks we can combine and the result we'd see.
The Supernetting/CIDRchart
There are four columns available in our chart:
The CIDR Block, the Supernet Mask, Number of Class C Networks and the Number of Hostscolumn.
Class C
CIDR Block
Supernet Mask
Number of Class C Networks
Number of Hosts
/14
255.252.0.0
1024
262144
/15
255.254.0.0
512
131072
/16
255.255.0.0
256
65536
/17
255.255.128.0
128
32768
/18
255.255.192.0
64
16384
/19
255.255.224.0
32
8192
/20
255.255.240.0
16
4096
/21
255.255.248.0
8
2048
/22
255.255.252.0
4
1024
/23
255.255.254.0
2
512
/24
255.255.255.0
1
254
/25
255.255.255.128
1/2
126
/26
255.255.255.192
1/4
62
/27
255.255.255.224
1/8
32
/28
255.255.255.240
1/16
16
/29
255.255.255.248
1/32
8
/30
255.255.255.252
1/64
4
I am going to explain the meaning of each column, although you probably already know most of them.
The CIDR Block
The CIDR Block simply represents the number of bits used for the subnet mask. For example,/14 means 14 bits assigned to the subnet mask, it is a lot easier telling someone you have a14 bit subnet mask rather than a subnet mask of 255.252.0.0 :)
Note: In the above paragraph, I called the 14 bits as a subnet mask, when in fact it's a supernet mask, but because when you configure any network device, the field you will need to enter the value is usually named as the 'subnet mask', I decided to name it 'subnet mask' aswell, in order to avoid confusion.
I'd like you to pay particular attention to the CIDR Block /24, and /25 to /30. These blocks are highlighted in yellow and blue because I want them to grab your attention :)
When we use a CIDR Block of 24 (24 bit subnet mask) we are not Supernetting ! This is a default subnet mask for a Class C network. With CIDR Blocks /25 to /30 we are actuallySubnetting and not Supernetting !
Now you might wonder why I have them in the chart. The fact is that those particular CIDR Blocks are valid, regardless of whether applying them to a network means we are Subnettingand not Supernetting. If you have dealt with any ISPs and IP Address assignments, chances are you would have been given your IP Addresses in CIDR format.
A good example is if you wanted a permanent connection to your ISP and only required 2 IP Addresses, one for your router and one for your Firewall, you would be assigned one /30 CIDRBlock. With such a subnet mask you will have 4 IP Addresses, from which 2 will be reserved (one for the Network address and one for the Broadcast address) and you're left with 2 that you can assign to your hosts (router and firewall).
The Supernet Mask
Basically, this is your Subnet mask. When you configure the devices that will be attached to the specified network, this is the value you will enter as a Subnet mask. It's also the decimal value the CIDR Block specifies. For example, a /24 CIDR block means a 24 bit Subnet mask, which in its turn translates to 255.255.255.0 :) Simple stuff !
Number of Class C Networks
This number shows us how many Class C Networks are combined by using a specific Supernet mask or, if you like, CIDR Block. For example, the /24 CIDR Block, 255.255.255.0 Supernet mask is 1 Class C Network, whereas a /20 CIDR Block, 255.255.240.0 Supernet mask is 16 Class C networks.
Number Of Hosts
This value represents the number of hosts per Supernet. For example, when we use a /20CIDR Block, which means a Subnet (or Supernet) mask of 255.255.240.0, we can have up to4096 hosts. Pretty straightforward stuff.
There is one thing you must be careful of though ! The value 4096 does not represent the valid, usable IP Addresses. If you wanted to find out how many of these IP Addresses you can actually use, in other words, assign to hosts, then you simply take 2 IP Addresses from that number (the first and last IP Address), so you're left with 4094 IP Addresses to play with :)
Why take 2 away ? You shouldn't be asking questions like that if you have read the IP and Subnetting sections but I'll tell you anyway :) One is reserved for the Network Address and one for the Broadcast Address of that network !
Summary
That completes the explanation of the Supernetting/CIDR chart. You will see that Supernetting and Subnetting have quite a few things in common, and this is simply because they work on the same principle.
Again, if you have the whole topic, or certain sections hard to understand, you should give yourself a small break, and then come back for another round :)
My teacher asked me to explain why I was late for class.Photosynthesis is difficult to explain.
its a shape that cannot explain
good question!!! someone please help answer-question recorder
Science can explain how thing happen. Example, science can explain why you can walk without slipping. Without science, there would be no technology. Technology can make what we do simpler. With the help of technology, everything is simpler.
Information is facts provided or learned about something or someone e.g. He is one year old
If you combine multiple classful networks it is supernetting, when you make them smaller you are subnetting . CIDR is a condition where you no longer consider the classful boundries. You no longer need to think of the words subnetting or supernetting really because everything is a simple division between network and host.
Supernetting
what do u mean by precipitation? explain by giving an example
What are conditional connectives? Explain use of conditional connectives with an example
define BCNF. Explain with appropriate example
CLASSFUL ROUTING PROTOCOL. It means it will not carry the routing mask information while routing updates or routing advertisements. it will carry just only the ip-address information's. It will assume just default mask information's. Example : class-A 255.0.0.0 Class-B 255.255.0.0 Class-C 255.255.255.0 So classful routing protocols will not support the VLSM and Supernetting Example of classful routing protocols is 1. RIP V1 2. IGRP CLASSLESS ROUTING PROTOCOL These kind of routing protocols will carry the subnet mask information's while doing the routing updates or routing advertisements. So it will support the VLSM and Supernetting, also support noncontiguous networks Example RIP V2 EIGRP OSPF CLASSFUL ROUTING PROTOCOL. It means it will not carry the routing mask information while routing updates or routing advertisements. it will carry just only the ip-address information's. It will assume just default mask information's. Example : class-A 255.0.0.0 Class-B 255.255.0.0 Class-C 255.255.255.0 So classful routing protocols will not support the VLSM and Supernetting Example of classful routing protocols is 1. RIP V1 2. IGRP CLASSLESS ROUTING PROTOCOL These kind of routing protocols will carry the subnet mask information's while doing the routing updates or routing advertisements. So it will support the VLSM and Supernetting, also support noncontiguous networks Example RIP V2 EIGRP OSPF
explain with help of an example, how FAT is different from inode.
"What are the benefits of measures of central tendency? Explain with an example
yes
1 Explain listing process with suitable example & Diagram
The idea is to use networks that are larger than a traditional (i.e., classful) network - especially, larger than a class-C network.
state out 5 example of communication barriers and explain them accordingly