ZyXEL Communications P-660HWP-D1, Руководство пользователя

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Appendix D IP Subnetting
P-660HWP-D1 User’s Guide
338
Example Eight Subnets
Similarly use a 27-bit mask to create eight subnets (000, 001, 010, 011, 100, 101, 110 and
111).
The following table shows class C IP address last octet values for each subnet.
The following table is a summary for class “C” subnet planning.
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
Table 143 on page 333 ) available for subnetting.
The following table is a summary for class “B” subnet planning.
Table 154 Eight Subnets
SUBNET
SUBNET
ADDRESS
FIRST ADDRESS
LAST
ADDRESS
BROADCAST
ADDRESS
1 0 1 30 31
2 32 33 62 63
3 64 65 94 95
4 96 97 126 127
5 128 129 158 159
6 160 161 190 191
7 192 193 222 223
8 224 225 254 255
Table 155 Class C Subnet Planning
NO. “BORROWED” HOST
BITS
SUBNET MASK NO. SUBNETS
NO. HOSTS PER
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
Table 156 Class B Subnet Planning
NO. “BORROWED” HOST
BITS
SUBNET MASK NO. SUBNETS
NO. HOSTS PER
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