Subnetting With Class A And Class B Networks - ZyXEL Communications ZYAIR G-4100 User Manual

ZyAIR G-4100 User's Guide
NO. "BORROWED" HOST BITS
3
4
5
6
7

Subnetting With Class A and Class B Networks.

For class "A" and class "B" addresses the subnet mask also determines which bits are part of the
network number and which are part of the host ID.
A class "B" address has two host ID octets available for subnetting and a class "A" address has three
host ID octets (see Chart J-1) available for subnetting.
The following table is a summary for class "B" subnet planning.
NO. "BORROWED" HOST BITS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BB
Chart 12 Class C Subnet Planning
SUBNET MASK
255.255.255.224 (/27)
255.255.255.240 (/28)
255.255.255.248 (/29)
255.255.255.252 (/30)
255.255.255.254 (/31)
Chart 13 Class B Subnet Planning
SUBNET MASK
255.255.128.0 (/17)
255.255.192.0 (/18)
255.255.224.0 (/19)
255.255.240.0 (/20)
255.255.248.0 (/21)
255.255.252.0 (/22)
255.255.254.0 (/23)
255.255.255.0 (/24)
255.255.255.128
(/25)
255.255.255.192
(/26)
255.255.255.224
(/27)
255.255.255.240
(/28)
255.255.255.248
(/29)
255.255.255.252
(/30)
255.255.255.254
(/31)
NO. SUBNETS NO. HOSTS PER SUBNET
8
16
32
64
128
NO. SUBNETS NO. HOSTS PER SUBNET
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
16384
32768
30
14
6
2
1
32766
16382
8190
4094
2046
1022
510
254
126
62
30
14
6
2
1
IP Subnetting