yaml switches: cisco1: vendor: cisco model: 2960 ip: 10.0.0.1 cisco2: vendor: cisco model: 3750 ip: 10.0.0.2 hp1: vendor: hp model: 1920 ip: 10.0.0.3

---

# Filtering only cisco switches

```python
import yaml

with open('switches.yaml') as f:
    switches = yaml.safe_load(f)

cisco_switches = {k: v for k, v in switches['switches'].items() if v['vendor'] == 'cisco'}

---

Getting the last host address in the 172.16.0.0/28 network

import ipaddress

network = ipaddress.IPv4Network('172.16.0.0/28')
last_host = str(list(network.hosts())[-1])
print(last_host)  # 172.16.0.14

---

Parsing dhcp_snooping_table into a list of dictionaries

dhcp_snooping_table = '''
00:E9:BC:3F:A6:50 100.1.1.6 FastEthernet0/20
00:E9:22:11:A6:50 100.1.1.7 FastEthernet0/21
'''

lines = dhcp_snooping_table.strip().split('\n')
dhcp_snooping_table_parsed = []
for line in lines:
    mac, ip, interface = line.split()
    dhcp_snooping_table_parsed.append({
        'mac': mac,
        'ip': ip,
        'interface': interface
    })

---

Class NetworkSubnet

import ipaddress

class NetworkSubnet:
    def __init__(self, network):
        self.network = ipaddress.IPv4Network(network)
        self.used_subnets = []

    def get_subnet(self, prefixlen):
        for subnet in self.network.subnets(new_prefix=prefixlen):
            if subnet not in self.used_subnets:
                self.used_subnets.append(subnet)
                return subnet
        return None

    def show_network_pool(self):
        all_subnets = list(self.network.subnets())
        available = [s for s in all_subnets if s not in self.used_subnets]
        return available

# Example usage
net = NetworkSubnet('192.168.0.0/24')
subnet = net.get_subnet(28)
print(subnet)  # 192.168.0.0/28
print(net.show_network_pool())

1. Example of a switches object in YAML format:

switches:
  - name: switch1
    vendor: cisco
    ip: 192.168.1.1
  - name: switch2
    vendor: juniper
    ip: 192.168.1.2
  - name: switch3
    vendor: cisco
    ip: 192.168.1.3

2. Transformation to keep only Cisco switches:

import yaml

with open('switches.yaml') as f:
    data = yaml.safe_load(f)

cisco_switches = [sw for sw in data['switches'] if sw['vendor'].lower() == 'cisco']

print(cisco_switches)

3. Getting the last host address in the network "172.16.0.0/28":

import ipaddress

network = ipaddress.ip_network('172.16.0.0/28')
last_host = network.broadcast_address - 1
print(last_host)  # 172.16.0.14

4. Parsing dhcp_snooping_table into a list of dictionaries:

dhcp_snooping_table = '''
MacAddress          IpAddress        Interface
00:E9:BC:3F:A6:50  100.1.1.6       FastEthernet0/20
00:E9:22:11:A6:50  100.1.1.7       FastEthernet0/21
'''

lines = dhcp_snooping_table.strip().split('\n')[1:]  # skip header

parsed = []
for line in lines:
    mac, ip, interface = line.split()
    parsed.append({"mac": mac, "ip": ip, "interface": interface})

print(parsed)

5. NetworkSubnet class with required methods:

from ipaddress import IPv4Network

class NetworkSubnet:
    def __init__(self, aggregate_network: str):
        self.aggregate = IPv4Network(aggregate_network)
        self.available_subnets = [self.aggregate]

    def get_subnet(self, length: int) -> IPv4Network:
        for i, subnet in enumerate(self.available_subnets):
            if subnet.prefixlen <= length:
                # Split the subnet into smaller ones
                subnets = list(subnet.subnets(new_prefix=length))
                if subnets:
                    allocated = subnets[0]
                    # Update available subnets pool
                    remaining = subnets[1:] + self.available_subnets[:i] + self.available_subnets[i+1:]
                    self.available_subnets = remaining
                    return allocated
        raise ValueError("No available subnets of the required size")

    def show_network_pool(self) -> list[IPv4Network]:
        return self.available_subnets

# Example usage
net = NetworkSubnet(aggregate_network="172.16.0.0/24")
net_1 = net.get_subnet(length=26)
print(f"{net_1=}")  # 172.16.0.0/26
print(net.get_subnet(length=25))  # 172.16.0.64/25
print(net.get_subnet(length=30))  # 172.16.0.192/30
print(net.show_network_pool())