Below is Alex’s with explanations written in the margins. Part 1 – Address Classification & Default Masks | IP Address | Class | Default Subnet Mask | Network ID | Host ID | |-----------------------|-----------|-------------------------|----------------|--------------| | 10.250.1.15 | A | 255.0.0.0 | 10.0.0.0 | 250.1.15 | | 172.31.200.99 | B | 255.255.0.0 | 172.31.0.0 | 200.99 | | 192.168.5.10 | C | 255.255.255.0 | 192.168.5.0 | 10 | | 203.0.113.88 | C | 255.255.255.0 | 203.0.113.0 | 88 | | 8.8.8.8 | A | 255.0.0.0 | 8.0.0.0 | 8.8.8 |
| | Hosts needed | CIDR | Subnet mask | Network ID | |----------------|--------------|------|-------------------|-----------------| | Headquarters | 2000 | /20 | 255.255.240.0 | 10.0.0.0/20 | | Branch1 | 500 | /22 | 255.255.252.0 | 10.0.16.0/22 | | Branch2 | 200 | /24 | 255.255.255.0 | 10.0.20.0/24 | | WAN1 | 2 | /30 | 255.255.255.252 | 10.0.21.0/30 | | WAN2 | 2 | /30 | 255.255.255.252 | 10.0.21.4/30 | Below is Alex’s with explanations written in the margins
Alex later passes the CCNA – thanks to the methodical practice of subnetting by hand. Below is Alex’s with explanations written in the margins
| | CIDR | Subnet Mask | Network ID | Hosts usable | |-------------|----------|----------------|----------------|------------------| | LAN A | /25 | 255.255.255.128 | 192.168.10.0 | 126 | | LAN B | /26 | 255.255.255.192 | 192.168.10.128 | 62 | | LAN C | /27 | 255.255.255.224 | 192.168.10.192 | 30 | | WAN link | /30 | 255.255.255.252 | 192.168.10.224 | 2 | Below is Alex’s with explanations written in the margins