Basic Switching Concepts and Configuration

Study Notes

Discussion of switch operation, Layer 2 and Layer 3 switching, and basic switch configuration.
Lead-in to VLAN concepts, highlighting the shift from general switching to more specific network segmentation techniques.

A networking device that connects multiple devices (computers, printers, servers) within a local area network (LAN).
Primarily functions at the Data Link Layer (Layer 2) but some models can operate at the Network Layer (Layer 3) for routing.

A conceptual framework consisting of seven distinct layers used to understand and implement network protocols.
Each layer has a specific function and interacts with adjacent layers, ensuring interoperability among different network devices.

Operates at the Data Link Layer (Layer 2) of the OSI model, primarily forwarding data frames within the local network based on MAC addresses.

MAC Address-Based Forwarding:
- Forwards frames based on destination MAC address; checks its MAC address table (CAM table) for port associations.
MAC Address Table:
- Dynamically maintained table mapping MAC addresses to switch ports, allowing the switch to learn and store active devices.
Frame Filtering and Forwarding:
- Unicast: forwards frames only to the port associated with known destination MAC addresses.
- Unknown MAC addresses lead to flooding frames to all ports except the source.
- Broadcast/multicast frames sent to all ports except the source port.
No Routing Capabilities:
- Does not route IP packets between different networks; all devices connected must be within the same broadcast domain.
Collision Domains:
- Each port is a separate collision domain, reducing collisions by providing dedicated bandwidth to connected devices.
Broadcast Domain:
- All ports on a Layer 2 switch are in the same broadcast domain, sending broadcast frames (like ARP requests) to all ports.
VLAN Support:
- Supports Virtual Local Area Networks (VLANs) to segment a physical network into multiple logical networks, enhancing security and performance.
Spanning Tree Protocol (STP):
- Prevents network loops in redundant path environments by ensuring only one active path exists between devices while blocking others.

Fundamental device for managing data traffic within a LAN, relying on MAC addresses for forwarding.
Provides connectivity, minimizes collisions, supports VLANs, but lacks routing capabilities found in Layer 3 switches or routers.