Building and Managing Networks
1. Network Addressing
IPv4 vs. IPv6: Structure and Differences
IPv4
- An IPv4 address consists of 32 bits, e.g.,
192.168.1.1
.
- Represented in decimal notation: four numbers between 0 and 255.
- Limitation: Only about 4.3 billion addresses are available.
IPv6
- An IPv6 address consists of 128 bits, e.g.,
2001:0db8:85a3:0000:0000:8a2e:0370:7334
.
- Written in hexadecimal: eight groups of four hexadecimal characters.
- Advantage: Virtually unlimited addresses.
Subnetting and CIDR
Subnetting
- Dividing a network into smaller subnets to use addresses efficiently.
- Example:
192.168.1.0/24
represents 256 addresses in the subnet.
CIDR (Classless Inter-Domain Routing)
- Enables flexible addressing without fixed classes (A, B, C).
- Example:
192.168.1.0/27
= 32 addresses (30 usable).
Private vs. Public IP Addresses
- Private Addresses: Local to the LAN, not directly accessible on the internet (e.g.,
192.168.0.0/16
).
- Public Addresses: Directly reachable on the internet.
2. Network Design
Network Topologies
Star Topology
- Each device is connected directly to a central switch.
- Advantage: Failure of one device does not affect the network.
Ring Topology
- Devices are connected in a ring.
- Advantage: Equal load distribution, but failure of one device breaks the network.
Mesh Topology
- Each device is connected to multiple other devices.
- Advantage: High redundancy and fault tolerance.
VLANs (Virtual LANs)
- Logical division of a physical network into multiple subnets.
- Example: Separating IT and guest networks in a company.
3. Network Management
SNMP (Simple Network Management Protocol)
- Allows monitoring and controlling network devices.
- SNMP Components:
- Manager: Monitors the network (e.g., Zabbix).
- Agent: Runs on each monitored device.
- MIB (Management Information Base): Database of manageable network parameters.
Network Monitoring
- Tools like Nagios, Zabbix, or Prometheus provide detailed insights into network status.
QoS (Quality of Service)
- Prioritization of traffic, e.g., for video calls or critical services.
- Example: Reserving bandwidth for specific applications.
Conclusion
Network addressing and design are the foundations of efficient and secure networks. The next chapter will cover network security, including firewalls and VPNs.