How to work with VLSM in the Cisco CCNA -Part1

[@concepcionz17]

People in order to understand VLSM you NEED to know how to subnet, Great Video, fully understandable (Only explained what is VLSM) lol danscourses

[@zevendonk2300]

Thanks for you're tutorials. This video's about subnetting made me clear about how it's done. My exam went VERY well thanks to you're skill to teach people. thanks and regards from Belgium :D

[@danscourses]

@sagetajr Yes you can start with 192.168.12.0 but if you need to divide it up into separate subnets then yes you need to come up with a plan for dividing the networks into smaller groups. If you used a /27 on every subnet that would make 8 subnetworks 192.168.12.0, 192.168.12.32, 192.168.12.0, 192.168.12.64, 192.168.12.96, 192.168.12.128, 192.168.12.160, 192.168.12.192, and 192.168.12.224,

[@unclephil4494]

Bit set in the magic number spot. Ding! Light came on. Thank you very much, Sir.

[@danscourses]

@TheDynamix10 I think you mean you can't use the 192.168.1.1 host number more than once, but absolutely, you can divide the 192.168.1.0 network into multiple subnets. That "is" subnetting.

[@danscourses]

@sagetajr only on the older IOS' could you not use the first and last subnets with the newer versions of the Cisco IOS you can use all of the subnets.

[@SvenCheddar]

Thank you for.making this lol ugh my head stopped hurtibg for a sec watching this. I didnt realize the last network bit is how many ips i can use per subnet that saves me alot of time.

[@lal6799]

Question. at 3:00 video time stamp, why did you choose to borrow three bits from the last Octec?

[@xxxdannyxxx]

@STUNTS1516 he basically borrow 3 from the last octet. remember, 255 in binary is all 1. in each octet, the size of it 8 digits is binary. in the last octet, he borrowed 3 digits, which have to be "1" because you are adding to the MASK. 3 digits were pick because he needed a minimum of 7 subnets. so 3 octets that have 255 is 24, and he borrow 3 from the last octet which gives you 27

[@puru2812]

great video,,,,,,,i will be looking for more videos like that

[@onrajeev]

I think the host number is 30 per network as 2^(number of bits left after borrowing)-2 is host number. We are borrowing 3 so left is 5 , 2^5-2=32-2=30.

[@aminahmedabib5832]

This great video, it is realy useful ,thanks alot

[@isaiahgovea2319]

love the video, great details and info

[@aikdds4769]

Very easy to understand :) thanks you.

[@IKnowALittleCuban]

I agree with onrajeev, there are 30 hosts/network. You can't count network and broadcast addresses.

[@TheSword3000]

@STUNTS1516 Think of it like this - the first 3 octets equal 24. In the 4th octet 3 bits were borrowed, thus u have 27 total. Let me know if this helps.

[@ramirez368]

Great example Dan...2N it gives you the amount of Network that you need right...? and 2N-2 it gives you the amount of Usable host you can have....so 2*2*2=8 so it is in the range of the 7 network that you need.

[@adriansrfr]

(2^n)-2 only applies to hosts, not networks.

[@STUNTS1516]

Im just a bit confused hopefully you can clear something up for me, Do you mind explain were the /27 actually comes from?..

[@yahelisrael6958]

Please explain for new learners that the 32 is the block size

[@ViperOne999]

Very nice... Thnx

[@shakibacademia3639]

Thank you , sir .

[@TheSword3000]

great job! I really appreciated this vid!

[@didancc]

@JackBennett27 I agree. He's awesome!

[@seanwilkerson7558]

According to your other subnetting videos the magic number should be 16. Does the magic number change when doing VLSM?

[@sagetajr]

@danscourses oh man thanks for the update.. i did not know that

[@happybeltran4286]

Nice video, but need more detailed explanation...like why did you borrowed 3 bits in the 4th octet

[@ahcbd]

actually idea of borrowing 3 1's is came from the requirement of number of sub network i.e. seven here. Note that, to have any number of sub networks you need to choose between 2, 4, 8, 16, 32, 64, 128. so we must to chose at least 8 subnet option to have 7 sub network. now, 8 = 2 to the power 3 thus the 3 came from. but to my understanding it's not required. you just choose among between 2, 4, 8, 16, 32, 64, 128

[@sagetajr]

@danscourses sweet! , thank you for your insight.

[@sagetajr]

can i use 192.168.12.0 ? would that have the same /27 sub-net mask or no?

[@martincampero7525]

What about the 2n-2, 2*2*2=8-2=only 6 networks, is it different when you are doing a VLSM?

[@SkyKing02]

good question. i don't understand why he's using 11100000 but not 11110000.

[@romanzaytsev5527]

SkyKing02 N-2 applies to the number of hosts in the subnet.

[@concepcionz17]

Martin Campero -2 Only applies to the host when you count from right to left, (Network and Broadcast) from left to right is to find the subnet

[@juanogol1]

so the number of possible subnets is 2^​x , so /27 have 11100000 where x is the number of 1s and that is why 8 networks... correct?

[@idrishussain8303]

Great video. However, you should give us some exercises to do. As this will enable us to see If we understood it and, the answer to be displayed in at the end.

[@ginapacubas6653]

Ip of the routers must be in diff networks

[@macgihan]

thank you very much :)

[@pempek8282]

very helpful, thanx

[@sagetajr]

But /27 isnt enough it only gives 6 usable nets out of 8 subnets : 8 subnets - 2(net/broadcast)= 6 .....wouldnt a /28 be used instead? which will give out 14 usable subnets out of 16 subnets : 16 subnets - 2(net/broadcast)= 14....

[@AjaySingh-qh4rt]

One confusion.. I think if I borrow 3 bits then the valid host will be 6

[@MrWxoxw]

Thanks dear, my respect

[@SeanYves09]

@danscourses Wait a minute, /27 gives you 16 possible networks not 8 soo....

[@oemdzi]

Its great tutorial, but first you have to be good at "regular" subnetting. Ty for this video;)

[@Genxgt]

got this one in class: 192.168.156.0/22 host:128, 90, 60, 60, 30, 2, 2, 2 and was to start the addressing from 192.168.157.0.. . I realized that I was way out on vlsm.... run this for me

[@ezzab69]

thanks man

[@Flacksh0t]

Nice

[@nirupopy]

New learners will find difficulty to understand you

[@nick1837]

He just didn’t show us the process of how he got those IP Addresses and CIDRS. For example, write all of the numbers on the board, (or a piece of paper), including your CIDRS, SM, Network numbers, etc. From there, you’re gonna have to draw your line (or wall) to the nearest subnet mask greater than the one they give you in your IP Address. Draw that wall, and plug in the numbers. Afterwards, you go from there, and do the rest of the problem step by step according to VLSM (not regular class a, b, or c subnetting, VLSM subnetting). I find the wall to be the easiest way to learn subnetting/VLSM. He also forgot how to draw out how he breaks down the numbers until he gets those new IP Addresses and CIDRS. (It took me an entire semester to get VLSM).

[@sungsam1318]

Whàaaaaaaat. Oh my good¡!!!!!!!! Ohhhhhjhhhjhjhh

[@Eiffelism]

routa routa routa lol

[@cocxel]

CCNA SUBNETTING ** COCXEL.COM

[@XwpisONOMA]

At around 6 min you say that since I borrowed 3 bit for the network then I can have 8 subnets so my magic number is 32 and then you proceed to fill in just 7 networks ignoring subnet starting at .224 completely and then you keep saying 8 networks a few times and finally you write but in CCNA blah blah and then type 7 networks etc etc. I mean come on man. Are you that desperate, for YT monetization? First master the material and then pretend you are an instructor. Common sense and some dignity please!

[@elppfer]

STFU

[@lamontemagnifico7149]

Go to hell man....he has way more class and dignity than your whining ass

[@danscourses]

@sagetajr Yes you can start with 192.168.12.0 but if you need to divide it up into separate subnets then yes you need to come up with a plan for dividing the networks into smaller groups. If you used a slash 27 on every subnet that would make 8 subnetworks 192.168.12.0, 192.168.12.32, 192.168.12.0, 192.168.12.64, 192.168.12.96, 192.168.12.128, 192.168.12.160, 192.168.12.192, and 192.168.12.224,