10.1 Layer 3 Switching Explained
Key Concepts of Layer 3 Switching
Layer 3 Switching, also known as IP Switching, combines the functionality of traditional routers and switches. Key concepts include:
- Routing: The process of forwarding packets between different networks based on IP addresses.
- Switching: The process of forwarding packets within the same network based on MAC addresses.
- Hardware-Based Routing: Utilizing specialized hardware to perform routing functions at high speeds.
- Integrated Routing and Switching: Combining routing and switching functionalities in a single device.
- VLAN Routing: Routing between different Virtual LANs (VLANs) within the same Layer 3 Switch.
Routing
Routing is the process of forwarding packets between different networks based on IP addresses. Layer 3 Switches perform routing functions by examining the destination IP address of each packet and determining the best path to forward it.
Example: A Layer 3 Switch receives a packet with a destination IP address of 192.168.2.10. The switch consults its routing table to determine the best interface to forward the packet to reach the destination network 192.168.2.0/24.
Switching
Switching is the process of forwarding packets within the same network based on MAC addresses. Layer 3 Switches perform switching functions by examining the destination MAC address of each packet and forwarding it to the appropriate port.
Example: A Layer 3 Switch receives a packet with a destination MAC address of 00:1A:2B:3C:4D:5E. The switch consults its MAC address table to determine the port to which the device with that MAC address is connected and forwards the packet accordingly.
Hardware-Based Routing
Hardware-Based Routing involves utilizing specialized hardware, such as ASICs (Application-Specific Integrated Circuits), to perform routing functions at high speeds. This allows Layer 3 Switches to handle large volumes of traffic efficiently.
Example: A MikroTik RouterBOARD equipped with an ASIC can perform routing functions at gigabit speeds, making it suitable for high-performance networking environments.
Integrated Routing and Switching
Integrated Routing and Switching combines the functionalities of both routers and switches in a single device. This allows for efficient management and reduced complexity in network design.
Example: A MikroTik RouterBOARD can act as both a router and a switch, providing routing between different networks while also switching packets within the same network.
VLAN Routing
VLAN Routing involves routing between different Virtual LANs (VLANs) within the same Layer 3 Switch. This allows for logical separation of network traffic while still enabling communication between different VLANs.
Example: A Layer 3 Switch can route traffic between VLAN 10 (Sales Department) and VLAN 20 (Marketing Department), ensuring that each department's traffic is isolated while still allowing inter-department communication.