3.CCNP ENCOR 350-401 - Switch Fundamentals

Switch Fundamentals

This video is the second in a CCNP ENCOR series.
The topic is switches, leading into MAC address tables in the next video.
Basic switch concepts already covered in the CCNA 200-301 series will be reviewed.

A switch is a device used to connect multiple systems in a Local Area Network (LAN).
Switches connect devices within the same network.
Example: Connecting two PCs directly using Ethernet cables and LAN cards works for two devices.
For three or more PCs, a switch is necessary as each PC has only one LAN card.
The Ethernet cables from each PC connect to the switch, allowing all PCs to communicate.

Manageable Switch: Allows configuration via CLI, VLAN creation, Spanning Tree Protocol (STP) configuration, etc.
Unmanageable Switch: Plug and play; no CLI or configuration options.

Feature	Manageable Switch	Unmanageable Switch
Configuration	Yes, via CLI (Command Line Interface)	No CLI
VLAN Creation	Yes	No
Spanning Tree	Yes, STP configuration possible	No
Cost	More expensive	Less expensive (cheaper)
Console Port	Present	No console port
Management	Can manage and configure	Cannot manage; plug and play only

Layer 2 Switch: Operates at Layer 2 (Data Link Layer) of the OSI model.
Layer 3 Switch: Operates at Layer 3 (Network Layer) of the OSI model; also known as a multilayer switch.

Layer 3 switches can perform routing by using the ip routing command to enable routing
Layer 2 Switch: Forwards frames.
Layer 3 Switch: Forwards frames and can also perform routing.

Switches have multiple ports (e.g., 48 ports, 16 ports, 8 ports) depending on the model.
LEDs indicate the working status of the ports.
Console port is available for configuration (RJ45 or USB mini console port).

EVNG (Emulated Virtual Network Generator) can be used for labs.
Packet Tracer and GNS3 can also be used.
Not all commands function the same way in Packet Tracer. So, GNS3 or EVNG is better.
In EVNG Right-click > Node > IOL > Select L2 or L3 switch.
You can change the icon of the switch
You must have enough RAM to run the switch (1 GB).
Connect the switch by dragging cable > select the interfaces to connect.
Start the selected nodes.
Double click to open the console
To check version in enable mode type command: show version
Sample configuration- Create new VLAN command: VLAN 10 name is Sales Exit and then type show VLAN brief
You can add port in a VLAN, first go in Interface e0\0 using command interface e0\0 followed by command switchport mode access followed by command switchport access VLAN 10 and you can use command show VLAN brief to see which ports are up
You can put duplex full using command: interface range e0\1 - 3 followed by command duplex full

Catalyst was a company that was acquired by Cisco; these switches are now under the Cisco name.

Modular switches allow adding or removing modules to increase or decrease the number of ports.
You can add or remove modules depending on the requirements. They use screw type connections.

Configure two hosts on separate switches.
Ensure VLANs are configured correctly.
Set the port to trunk using command:
- switchport trunk encapsulation dot1q
- switchport mode trunk
Remember to enable IP routing by using command ip routing for Layer 3 switches.