DevNet Associate DEVASC 200-901 Official Certification Guide by Adrian Iliesiu (z-lib.org)

Subn

et 7

192.168.0

.192

192.168.0

.223

192.168.0.193 to

192.168.0.222

Subn

et 8

192.168.0

.224

192.168.0

.255

192.168.0.225 to

192.168.0.254

New subnets can be easily created to accommodate any
number of devices. In the previous example, each subnet
can address up to 30 devices, but the subnets can be
further subnetted, if needed. By borrowing additional
bits from the host section, subnet masks of /28, /29, and
even /30 can be specified to create new subnets for 2 =
16 − 2 = 14, 2 = 8 − 2 = 6, or 2 = 4 − 2 = 2 hosts in each
subnet. /30 subnets are especially useful on point-to-
point serial connections between two routers—for
example, where there are only 2 devices connected and
there is no point in using larger subnets as that would
only lead to wasted addresses. Table 16-7 provides a
breakdown of the subnet masks from /24 to /32, their
binary representations, and the number of subnets and
hosts for each subnet.

Table 16-7 Subnet Mask Representations and the

Number of Subnets and Hosts for Each

Decimal Subnet

Mask

Binary Subnet

Mask

CID

R

Subne

ts

Hosts per

Subnet

255.255.25

5.255

11111111.11111111.111111111.

11111111

/

3

2

No

ne

N

/

A

255.255.25

5.254

11111111.11111111.111111111.

11111110

/

3

1

No

ne

N

/

A

255.255.25

5.252

11111111.11111111.111111111.

11111100

/

3

0

64 2

4

3 2