了解子网划分

Question

Assume your company is given an address of 200.5.16.0/24, 5 subnets are required.

I found that: Binary: 1111111.11111111.11111111.111000

Decimal: 255.255.255.224

Create a table that contains the network addresses of the subnets created within your network? Write down the Network Addresses, 1st and 2nd valid IP addresses in CIDR

(table displayed in below link)

http://gyazo.com/d93608e491c5197b21d0d64c34c3904a

Can someone do the first few for me and explain the process on how to do it? Thanks

Answer 1

The process of dividing a network into smaller network sections is called subnetting. This can be useful for many different purposes and helps isolate groups of hosts together and deal with them easily.

Each address space is divided into a network portion and a host portion. The amount the address that each of these take up is dependent on the class that the address belongs to. For instance, for class C addresses, the first 3 octets are used to describe the network. For the address 192.168.0.15, the 192.168.0 portion describes the network and the 15 describes the host.

By default, each network has only one subnet, which contains all of the host addresses defined within. A netmask is basically a specification of the amount of address bits that are used for the network portion. A subnet mask is another netmask within used to further divide the network.

Each bit of the address that is considered significant for describing the network should be represented as a "1" in the netmask.

For more details, please r

http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html

Answer 2

You already figured out that with this mask 1111111.11111111.11111111.11100000 you can create 5 networks, just put numbers in them:

Mask: 11100000
Subnetworks:
    00000000 = 0
    00100000 = 32
    01000000 = 64
    01100000 = 96
    10000000 = 128
    10100000 = 160 - 192

The problem here is that you are not using the upper 64 addresses (192-255).

Alternative

You can make 4 subnetworks and split the last one:

Mask: 11000000
Subnetworks:    
    00000000 = 0
    01000000 = 64
    10000000 = 128
    11000000 = 192  (split this one)

Subnetwork: 200.5.16.192/26
Mask: 11100000
Subnetworks:
    11000000 = 192
    11100000 = 224