Subnetting help

zeb1

hey all trying to get around subnetting this one is from trancender

Your company uses the Class C network address 192.168.50.0/24. You are required to assign network addresses so that Los Angeles can support 99 hosts, Denver can support 43 hosts, Phoenix can support 17 hosts and Seattle can support 7 hosts. All of your routers support classless interdomain routing (CIDR), variable-length subnet masks (VLSMs) and the use of subnets that contain all 0s and all 1s.

LA needs 99 host so it needs 7bits 10000000 (i use 99+1 then convert to bin)
so i get 192.168.50.128/25

Denver needs 43 host so 6bits 11000000
192.168.50.192/26

Phoenix needs 17 host so 8bits 11100000
192.168.50.224/27

Seattle needs 7 host so 4bits 11110000
192.168.50.240/28

i get my end Subnet Mask by 128+64+32+16+8+4+2+1
so LA 10000000 = 128
Denver 11000000 = 192 etc:

Though i am wrong can someone enlighten me on what im doing wrong. Thanks

Should add their answers
LA = 192.168.50.0/25
D = .168/26
P = .192/27
S = .224/28

astorrs

Sounds like you had the right subnet types, but why did you choose to start LA at 128? What was wrong with 0?

zeb1

The reason i used .128 is because since there are 7 bits for the client, i used the left-most 1 bit for the network. The 1st left most bit added up = 128????

Sorry im a little retarded when it comes to this

georgemc

Zeb,
It looks like you're confusing your subnet mask with your actual subnets. You're coming up with the right mask but don't seem to be applying them correctly.

zeb1 wrote:

hey all trying to get around subnetting this one is from trancender

Your company uses the Class C network address 192.168.50.0/24. You are required to assign network addresses so that Los Angeles can support 99 hosts, Denver can support 43 hosts, Phoenix can support 17 hosts and Seattle can support 7 hosts. All of your routers support classless interdomain routing (CIDR), variable-length subnet masks (VLSMs) and the use of subnets that contain all 0s and all 1s.

LA needs 99 host so it needs 7 bits 10000000 (i use 99+1 then convert to bin)
so i get 192.168.50.128/25

A /25 or 255.255.255.128 subnet mask applied to 192.168.50.128/24 will give you two possible subnets:

192.168.50.0 - 127 /25
or
192.168.50.128-255 /25

Typically you'd want to place your larger subnets near the beginning of your available address range. So well use 192.168.50.0 /25 for LA

Denver needs 43 host so 6 bits 11000000
192.168.50.192/26

A /26 or 255.255.255.192 subnet mask applied to 192.168.50.128/24 will give you four possible subnets:

192.168.50.0 - 63 /26
or
192.168.50.64 - 127 /26
or
192.168.50.128 - 191 /26
or
192.168.50.192 - 255 /26

Once again you want to place your larger subnets near the beginning of your available address range. So well use 192.168.50.128 /26 for Denver Remember, the first two 6-bit subnets (.0 -.63 and .64 - .127) are being used for LA (.0 - .127)

Phoenix needs 17 host so 5 bits 11100000
192.168.50.224/27

A /27 or 255.255.255.224 subnet mask applied to 192.168.50.128/24 will give you eight possible subnets:

192.168.50.0 - 31 /27
or
192.168.50.32 - 63 /27
or
192.168.50.64 - 95 /27
or
192.168.50.96 - 127 /27
or
192.168.50.128 - 159 /27
or
192.168.50.160 - 191 /27
or
192.168.50.192 - 223 /27
or
192.168.50.224 - 255 /27

Once again you want to place your larger subnets near the beginning of your available address range. So well use 192.168.50.192 /27 for Pheonix Remember, the first six 5-bit subnets (.0 - .31, .32 -.63, .64 - .95 and .96 - .127 for LA, and .128 - .159 and .160 - .191 for Denver) are being used for LA (.0 - .127) and Denver (.128 - .191).

Seattle needs 7 host so 4bits 11110000
192.168.50.240/28

You should be able to figure this one out now.

Though i am wrong can someone enlighten me on what im doing wrong. Thanks

Hopefully, this has "enlightened" you.

George

zeb1

i think i have it, hopefully i dont forget before the test - Thursday!!!!

Cheers heaps for the help

georgemc

Good Luck!

Cingular

Wow, that was a very good explanation georgemc!

I had a good question lined up but I had answered it by the end of typing it, haha.


Oh well.