help figuring out CIDR notation
kyle01
Registered Users Posts: 2 ■□□□□□□□□□
in CCNA & CCENT
I have a network address of 136.15.224.0.
I have a max number of hosts of 100
i would need a host bits of 7
the largest subnet is 100, so it would require 7 host_id bits
number of subnets is 10
number of subnet_id bits needed is 4
the supernet is /21
the subnet mask works out to be /25.
which would i use for the CIDR? I am confused here, I have chosen /21 so far, as I have a network of 3 subnetworks, but I have to increment by 1 as 3 doesn't work, so I have chosen 4 subnet bits needed.
I am made a table of the subnetworks and their IP ranges (there would be 1 unused).
With the /25 CIDR, I cannot split the network into 4. it doesn't seem to compute, so the only other answer is /21.
Is this correct
::
I have a max number of hosts of 100
i would need a host bits of 7
the largest subnet is 100, so it would require 7 host_id bits
number of subnets is 10
number of subnet_id bits needed is 4
the supernet is /21
the subnet mask works out to be /25.
which would i use for the CIDR? I am confused here, I have chosen /21 so far, as I have a network of 3 subnetworks, but I have to increment by 1 as 3 doesn't work, so I have chosen 4 subnet bits needed.
I am made a table of the subnetworks and their IP ranges (there would be 1 unused).
With the /25 CIDR, I cannot split the network into 4. it doesn't seem to compute, so the only other answer is /21.
Is this correct
:: Comments
-
advanex1
Member Posts: 365 ■■■■□□□□□□
Maybe my old brain is confused, but are you trying to summarize routes? You're asking about trying to figure out a CIDR while also mentioning supernets.
Was the subnet mask for 136.15.224.0 not already given? Are you trying to determine what subnet mask/CIDR allows for a maximum of 100 hosts? I guess I'm just kind of confused on what you're asking.Currently Reading: CISM: All-in-One
New Blog: https://jpinit.com/blog -
kyle01
Registered Users Posts: 2 ■□□□□□□□□□
Maybe my old brain is confused, but are you trying to summarize routes? You're asking about trying to figure out a CIDR while also mentioning supernets.
Was the subnet mask for 136.15.224.0 not already given? Are you trying to determine what subnet mask/CIDR allows for a maximum of 100 hosts? I guess I'm just kind of confused on what you're asking.
All I am given is the network address, I also given the following information:
1. using fixed-length sub-net mask
2. subnetwork 1 = 1 router (100 hosts), subnetwork 2 = 4 routers (router 1 = 12 hosts, router 2 = 75 hosts, router 3 = 16 hosts and router 4 = 10 hosts).
The diagram thus contains, 7 LANs 1 Backbone and 2 Leased Lines.
I am struggling to find the correct subnet mask with CIDR. -
pinkiaiii
Member Posts: 216
im practising subnets and are you sure the questions isnt asking you to create subnets with following paramaters one for 100hosts,2 for 75 which is a bit odd,then 3 for 16 hosts and 4 for 10 ?
thus you could basically work with class c mask on that.
or either some sort of trick question thus you could use class b cidr of /25 giving you 512 subnets and 128 hosts per subnet,but i dont believe question is written out correctly,since it would amount to huge wastage of networks.