To calculate, it's 2^x. So if you need 14 devices, 2^1 = 2, 2^2 = 4, 2^3 = 8, 2^4 = 16. 16 > 14 devices so the 4th power is our magic number. there are 32 bits in a subnet mask, subtract the power from the subnet mask. 32 - 4 = 28. Now we know to support 14 devices, a /28 will work. Remember that you need 2 IP addresses for the network host and broadcast domain. So a network of 14 devices needs 16 addresses, and a network of 32 devices needs 34 addresses, etc...
That last part about adding it threw me off at first but I get it now. It’s figuring out what is left over and finding out which CIDR references the remainder. Hope I get something similar on the exam as I can do most of this in my head and counting fingers now.
What I found as a faster shorthand is when you lay out the CIDR notation in a graph starting at /9 and go 8 across before going down you'll get to /30 which is 2 shy. But if you also lay out the IP4 address binary conversion 128 64 32 16 8 4 2 1 you'll find they line up exactly with the CIDR notations specifically /25 lining up with 128. With this knowledge and subtracting the 2 addresses you need you end up with the same answers without the math. Don't think this will work as well when you start getting into the larger blocks of addresses. If you're curious for this graph Professor Messer made it in hit Network+ videos in the subnetting sections.
If /X represents the subnet and Y = 32 represents total bits in an IPv4 address. Then X - Y = N^2 is the total IP addresses, and N^2 -2 = Y is usable IP addresses available (Minus the broadcast and the network ID).
all you need to remember is that the cidr notation of /24 equals 256 hosts you can work it out from there - /25 is half of that and /23 is double :) also remember to take 2 off your number of hosts for broadcast address and network address - good luck with the exam
@@justatip An IPv4 address is composed of 32 bits. /24 means that the first 24 bits define the network. So you have the remaining 8 bits for the hosts. 2^8 2x(2x2x2x2x2x2x2x2) =256 addresses, as the first one defines the network and the last one is the broadcast, you have 254 effective addresses. Then use the same principle for the rest of the table. /23 means the first 23 bits define the network and the remaining 9 bits are the host. 2^9=512 addresses minus the first and last = 510 effective addresses. Generally the smaller the cidr notation the bigger the number of addresses. Hope that makes sense.
I appreciate all that you do. Your sims helped me pass my A+ 1001. But, I have to ask, you used a calculator. I'm sure we will not be able to use a calculator and I do not know how to get the correct answer. Thanks for any assistance you can give.
Is that CIDR calculator provided as part of the exam or are the CIDR’s already provided? I’m curious who calcultes Sales 57 devices /26 Hr 23 devices /27 …. Etc….
Magic number if 26 is 62 as you go up you half that number then subtract 2 as you go down you double and subtract 2 so /24= 254 a /25 =126 a /26=62 but remember to subtract 2
Just passed Network+! Your videos were of great help. A huge thanks for all you do.
Congratulations
just passed and this was on the test, cheers bro!!
Congratulations
the new 008 exam?
@@trevincurrey6752 yessir
@@LuigiYT1 What resources did you use to study? I am studying right now but man I am feeling overwhelmed..
To calculate, it's 2^x. So if you need 14 devices, 2^1 = 2, 2^2 = 4, 2^3 = 8, 2^4 = 16. 16 > 14 devices so the 4th power is our magic number.
there are 32 bits in a subnet mask, subtract the power from the subnet mask. 32 - 4 = 28.
Now we know to support 14 devices, a /28 will work.
Remember that you need 2 IP addresses for the network host and broadcast domain. So a network of 14 devices needs 16 addresses, and a network of 32 devices needs 34 addresses, etc...
awesome thank you for this
That last part about adding it threw me off at first but I get it now. It’s figuring out what is left over and finding out which CIDR references the remainder.
Hope I get something similar on the exam as I can do most of this in my head and counting fingers now.
What I found as a faster shorthand is when you lay out the CIDR notation in a graph starting at /9 and go 8 across before going down you'll get to /30 which is 2 shy. But if you also lay out the IP4 address binary conversion 128 64 32 16 8 4 2 1 you'll find they line up exactly with the CIDR notations specifically /25 lining up with 128. With this knowledge and subtracting the 2 addresses you need you end up with the same answers without the math. Don't think this will work as well when you start getting into the larger blocks of addresses. If you're curious for this graph Professor Messer made it in hit Network+ videos in the subnetting sections.
If /X represents the subnet and Y = 32 represents total bits in an IPv4 address. Then X - Y = N^2 is the total IP addresses, and N^2 -2 = Y is usable IP addresses available (Minus the broadcast and the network ID).
VERY good video. Thank you for putting this together!
the CIDR calculator is not available during the exam, so a more in-depth explanation of how you got these answers would really help.
Thx for your comment, you're right, the CIDR calculator won't be available for the exam but you can practice it
all you need to remember is that the cidr notation of /24 equals 256 hosts you can work it out from there - /25 is half of that and /23 is double :) also remember to take 2 off your number of hosts for broadcast address and network address - good luck with the exam
@@vicki-annthornton8330 can you explain this trick a little more for me please
@@justatip
An IPv4 address is composed of 32 bits.
/24 means that the first 24 bits define the network. So you have the remaining 8 bits for the hosts.
2^8 2x(2x2x2x2x2x2x2x2) =256 addresses, as the first one defines the network and the last one is the broadcast, you have 254 effective addresses.
Then use the same principle for the rest of the table. /23 means the first 23 bits define the network and the remaining 9 bits are the host. 2^9=512 addresses minus the first and last = 510 effective addresses. Generally the smaller the cidr notation the bigger the number of addresses. Hope that makes sense.
@@vicki-annthornton8330 this makes beautiful sense so with this logic I can always solve how much IP address can I get with /xx correct?
In d n10 008 is packet tracer or command line used to config/troubleshoot router qs.tx
Can you go into the why? I can use a calculator
hi sir do you have BPQ for n10-008 exam?
I appreciate all that you do. Your sims helped me pass my A+ 1001. But, I have to ask, you used a calculator. I'm sure we will not be able to use a calculator and I do not know how to get the correct answer. Thanks for any assistance you can give.
Its really easy to calculate the number of usable ip's and total ip's in a given CIDR notation
magic numbers technique. look it up it’s ez
@@michaelbryant3643 thanks
Once you understand it all from a cheat sheet it’s very easy. Most people write it out on exam day
Is that CIDR calculator provided as part of the exam or are the CIDR’s already provided? I’m curious who calcultes
Sales 57 devices /26
Hr 23 devices /27 ….
Etc….
no. I am not sure why one was used in this video, as we can't have that on the test :/
I just took this test and none of the Pbq’s that you showed were on the test!!!
what pbq did you come across?
were there anyone else's videos that were on the test?
Is this on the latest exams or previous versions of exam like 007 ?? Is there a newer cable tester question in N10-008 ?? Can anyone confirm?
Very helpful information here
Sir do you have any multiple choice questions exercises for N+ exam?
Will upload soon
@@InformatikLab Could you do Network+ 008 PBQs??? Please!!
Please I failed my exam in December 7 2021, could you please do cidr notation in depth and for beginners please. I need to pass this second time .
Magic number if 26 is 62 as you go up you half that number then subtract 2 as you go down you double and subtract 2 so /24= 254 a /25 =126 a /26=62 but remember to subtract 2
@Saints Fan thanks hun. I passed already November last year. And am looking forward to my security plus.
@@ade8359 awesome well congratulations 🎉 to information technology
Do they allow you to use this cidr calculator on the exam? lol
They don't loll I put the calculator just in case you guys need to know where to find one
@@InformatikLab lol damn it!! Thanks your videos helped though.
Can anyone confirm if I this is also in 008
They are still available in 008