Huawei BM2022, User Manual

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Appendix D IP Addresses and Subnetting
BM2022 Users Guide
247
The following figure shows the company network after subnetting. There are now two sub-
networks,
A and B .
Figure 166
Subnetting Example: After Subnetting
In a 25-bit subnet the host ID has 7 bits, so each sub-network has a maximum of 2
7
2 or 126
possible hosts (a host ID of all zeroes is the subnets address itself, all ones is the subnets
broadcast address).
192.168.1.0 with mask 255.255.255.128 is subnet A itself, and 192.168.1.127 with mask
255.255.255.128 is its broadcast address. Therefore, the lowest IP address that can be assigned to
an actual host for subnet
A is 192.168.1.1 and the highest is 192.168.1.126.
Similarly, the host ID range for subnet B is 192.168.1.129 to 192.168.1.254.
Example: Four Subnets
The previous example illustrated using a 25-bit subnet mask to divide a 24-bit address into two
subnets. Similarly, to divide a 24-bit address into four subnets, you need to borrow two host ID
bits to give four possible combinations (00, 01, 10 and 11). The subnet mask is 26 bits
(11111111.11111111.11111111.
11 000000) or 255.255.255.192.
Each subnet contains 6 host ID bits, giving 2
6
- 2 or 62 hosts for each subnet (a host ID of all
zeroes is the subnet itself, all ones is the subnets broadcast address).
Table 108
Subnet 1
IP/SUBNET MASK NETWORK NUMBER
LAST OCTET BIT
VALUE
IP Address (Decimal) 192.168.1. 0
IP Address (Binary) 11000000.10101000.00000001. 00 000000
Subnet Mask (Binary) 11111111.11111111.11111111. 11 000000