You are given an IP address for a host 172.168.35.10/20 What is/are the

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24 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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1


You are given an IP address for a host 172.168.35.10/20


What is/are the


Subnet address?


Broadcast address?


The number of useable hosts available for this subnet?


The number of useable subnets available for this
network?


The assignable address range for this subnet?

2


Given an IP address for a host 172.168.35.10/20


The address is of class B.


/20


subnet mask:
11111111.11111111.11110000.00000000 =
255.255.240.0


256
-
240 = 16


Multiples of 16: 16, 32, 48, 64, 80, ….


Subnet address?


The third octet is 35 which is between 32 and 48, so we
choose the minimum value: 32


therefore, subnet address is
172.168.32.0

3


Broadcast address?


subnet address is
172.168.32.0

and the next subnet
address is
172.168.48.0

. We know that the broadcast
address is that of the next subnet address minus 1



172.168.48.0

-

1

------------------------


172.168.47.255

4


The number of useable hosts available for this subnet?


The address is of class B and
subnet mask is
11111111.11111111.11110000.00000000, so we borrowed 4
bits to make subnetting and 12 bits are left for hosts




x = 12


the number of useable hosts = 2
x
-
2 = 2
12
-
2 =
4094


5


The number of useable subnets available for this
network?


subnet mask is 11111111.11111111.11110000.00000000,
so we borrowed 4 bits to make subnetting


x = 4


the number of useable subnets = 2
x
-
2 = 2
4
-
2 =
14


6


The assignable address range for this subnet?

The subnet address is 172.168.32.0 and its broadcast
address is 172.168.47.255

The assignable address range is all addresses between the
subnet address and broadcast address:

172.168.32.1

172.168.32.2





174.168.47.254

7


Your organisation has been assigned a class B IP address
of 130.10.0.0


You require about 2000 subnetworks


Work out the


Subnet mask required for this subnet


The network and broadcast addresses for the first 5
useable subnets


The number of hosts for each subnet


The assignable address range of the first 5 useable
subnets

8


Your organisation has been assigned a class B IP address
of 130.10.0.0


You require about 2000 subnetworks

Number of subnets = 2
x
-
2, so we have to find the value of
x so as to get a value closer or equal to 2000.

If we choose x = 11, we get 2
11

-

2 = 2048


2 = 2046.

9


Subnet mask required for this subnet

The address is of class B and the default mask is

255.255.0.0. But, we need to borrow 11 (eleven) bits for
subnetting


11111111.11111111.
11111111
.
111
00000




subnet mask is
255.255.255.224

10


The network and broadcast addresses for the first 5
useable subnets:


256


224 = 32


Multiples of 32: 32, 64, 96, 128, 160, 192, …..




Subnet address



Broadcast address


1
st

subnet:
130.10.0.32



130.10.0.63


2
nd

subnet:
130.10.0.64



130.10.0.95


3
rd

subnet:
130.10.0.96



130.10.0.127


4
th

subnet:
130.10.0.128



130.10.0.159


5
th

subnet:
130.10.0.160



130.10.0.191

11


The number of hosts for each subnet

We borrowed 11 (eleven) bits for subnetting, so we are
left with 5 bits for host.


x = 5



number of hosts in each subnets = 2
x
-
2 = 2
5
-
2 =
30

12


The assignable address range of the first 5 useable
subnets:


The assignable address range is all addresses between
the subnet address and broadcast address.


1
st

subnet:
130.10.0.33

.....


130.10.0.62


2
nd

subnet:
130.10.0.65

…..


130.10.0.94


3
rd

subnet:
130.10.0.97

…..


130.10.0.126


4
th

subnet:
130.10.0.129

…..


130.10.0.158


5
th

subnet:
130.10.0.161

..…


130.10.0.190