[Day 6] 1. Some more commands

Interface is up, Line Protocol is up:
- The interface is operational, and there is both physical (Layer 1) and data link (Layer 2) connectivity. Connection has been successfully established.
Interface is down, Line Protocol is down:
- This could mean:
  1. Interface is administratively down: The interface has been manually disabled using the
```
shutdown
```
    command.
  2. There is no Layer 2 (Data Link Layer) connectivity or physical connection (Layer 1) is not functioning.
Interface is up, Line Protocol is down:
- This indicates a Layer 2 problem, potentially caused by:
  1. Clocking mismatch
  2. Encapsulation mismatch
  3. Keep alive failure
Interface is administratively down, Line Protocol is down:
- The interface has been manually shut down using the
```
shutdown
```
  command. To bring it back up, use the
```
no shutdown
```
  command.
Note: There is no scenario where the interface is down, but the line protocol is up.

Also referred to as BIA (Burned-in Address), physical address, or hardware address.

txload (transmit load), rxload (receive load), and reliability are values measured out of 255.

Runts: Frames smaller than 64 bytes.
Giants: Frames larger than 1518 bytes.
- Note: Runts and giants can be generated if a network interface card (NIC) is malfunctioning or rogue. Modern full-duplex switched Ethernet networks rarely experience collisions, but NIC failure or viruses can still lead to them.

A#show ip int: Displays all IP parameters for the interfaces.
A#show ip int brief: A concise version showing key parameters in a horizontal format. Often favored for quick checks.
A#show protocols: Displays the status of protocols configured on router or switch interfaces.
A#show version: Displays the system version, configuration register value, and other details. The default configuration register value is typically
```
0x2102
```
.