Appendix C IP Addresses and Subnetting

Subnet Planning

The following table is a summary for subnet planning on a network with a 24-bit network number.

Table 60 24-bit Network Number Subnet Planning

NO. “BORROWED”

SUBNET MASK

NO. SUBNETS

NO. HOSTS PER

HOST BITS

 

 

SUBNET

1

255.255.255.128 (/25)

2

126

 

 

 

 

2

255.255.255.192 (/26)

4

62

 

 

 

 

3

255.255.255.224 (/27)

8

30

 

 

 

 

4

255.255.255.240 (/28)

16

14

 

 

 

 

5

255.255.255.248 (/29)

32

6

 

 

 

 

6

255.255.255.252 (/30)

64

2

 

 

 

 

7

255.255.255.254 (/31)

128

1

 

 

 

 

The following table is a summary for subnet planning on a network with a 16-bit network number.

Table 61 16-bit Network Number Subnet Planning

NO. “BORROWED”

SUBNET MASK

NO. SUBNETS

NO. HOSTS PER

HOST BITS

 

 

SUBNET

1

255.255.128.0 (/17)

2

32766

 

 

 

 

2

255.255.192.0 (/18)

4

16382

 

 

 

 

3

255.255.224.0 (/19)

8

8190

 

 

 

 

4

255.255.240.0 (/20)

16

4094

 

 

 

 

5

255.255.248.0 (/21)

32

2046

 

 

 

 

6

255.255.252.0 (/22)

64

1022

 

 

 

 

7

255.255.254.0 (/23)

128

510

 

 

 

 

8

255.255.255.0 (/24)

256

254

 

 

 

 

9

255.255.255.128 (/25)

512

126

 

 

 

 

10

255.255.255.192 (/26)

1024

62

 

 

 

 

11

255.255.255.224 (/27)

2048

30

 

 

 

 

12

255.255.255.240 (/28)

4096

14

 

 

 

 

13

255.255.255.248 (/29)

8192

6

 

 

 

 

14

255.255.255.252 (/30)

16384

2

 

 

 

 

15

255.255.255.254 (/31)

32768

1

 

 

 

 

Configuring IP Addresses

Where you obtain your network number depends on your particular situation. If the ISP or your network administrator assigns you a block of registered IP

216

 

P-660RU-Tx User’s Guide