Networking Fundamentals

Cabling and Wi-Fi

• Wired connections have been around since the late 1960s, while wireless technology has existed for a long time, with Wi-Fi emerging in the early 1990s.
• Cables can be copper or fiber, with copper cables being cheaper and more common for short distances, while fiber cables are more expensive but better for longer distances.

Ethernet Protocol

• Ethernet is a protocol that devices in a network agree on, made up of many parts that describe types of cabling, speeds, and formatting.
• The layering system allows devices with different cables and speeds to communicate.

Cables

• Copper cables use electrical signals, which can be affected by outside interference.
• Fiber cables use light signals, which are not affected by interference.
• UTP (Unshielded Twisted Pair) cables are the most common copper cables, containing four pairs of wires that are twisted together to reduce crosstalk.
• Each pair has a solid color and a striped color, such as brown and striped brown.

Straight-Through and Crossover Cables

• Straight-through cables are used to connect a host to a switch, with the wires running straight through from one end to the other.
• Crossover cables are used to connect a host to another host or a switch to another switch, with the pairs swapped at one end.

Auto-MDIX

• Auto-MDIX is a technology that detects the type of cable used and adapts accordingly, so devices don't need to worry about using the right cable.

Fiber Cables

• Fiber cables use strands of glass, with single core fiber using a laser light and multi-mode fiber using an LED light.
• Single mode fiber is more expensive but can transmit data over longer distances, while multi-mode fiber is cheaper but limited to shorter distances.

Full and Half Duplex

• Full duplex devices can send and receive data at the same time, while half duplex devices can only do one at a time.
• Dual core fiber is full duplex, while single core fiber is half duplex.

Fiber Connectors

• Fiber cables have connectors, with LC and SC being the most common in data networking.
• Transceivers can be used to connect different types of cables, such as single mode and multi-mode fiber.

Wireless Networking (Wi-Fi)

• Wi-Fi uses radio waves to format and encode information, with access points connecting devices to the wired network.
• Wi-Fi does not use the Ethernet standard, but instead uses the IEEE 802.11 standard.

Network Addressing

• Devices on a network have two addresses: IP addresses and MAC addresses.

• MAC addresses are permanent and unique, assigned by the manufacturer, and used for communication within a LAN segment.

• IP addresses are chosen by network administrators, used for communication between LAN segments, and can be used to access hosts on different networks.

• Routers pass traffic between LAN segments, allowing devices to communicate across different networks.### How Routers Handle MAC Addresses

• When a message is sent, the router adds its own MAC address to the message and sends it.

• The router receives the message, strips its own MAC address off, and replaces it with the printer's MAC address.

• The router then forwards the message to the printer.

Key Facts about MAC and IP Addresses

• Hosts have both a MAC address and an IP address.
• A MAC address is used only within a Local Area Network (LAN) segment.
• An IP address can be used within a LAN segment, but it's also used to pass traffic to a different LAN segment.

MAC Addresses and Devices

• Computers and devices have MAC addresses.
• The question of who assigns these MAC addresses remains unanswered for now.
• A device may have more than one MAC address.

Cabling and Wi-Fi

• Wired connections have been around since the late 1960s, while wireless technology, specifically Wi-Fi, emerged in the early 1990s.

Ethernet Protocol

• Ethernet is a protocol that enables devices to communicate in a network, comprising multiple parts that describe cabling, speeds, and formatting.
• The layering system facilitates communication between devices with different cables and speeds.

Cables

• Copper cables use electrical signals, making them susceptible to outside interference.
• Fiber cables use light signals, which are immune to interference.
• Unshielded Twisted Pair (UTP) cables are the most common copper cables, consisting of four twisted pairs of wires to reduce crosstalk.

Straight-Through and Crossover Cables

• Straight-through cables connect a host to a switch, with wires running straight through from one end to the other.
• Crossover cables connect a host to another host or a switch to another switch, with the pairs swapped at one end.

Auto-MDIX

• Auto-MDIX is a technology that detects the type of cable used and adapts accordingly, eliminating the need for devices to worry about using the right cable.

Fiber Cables

• Fiber cables use strands of glass, with single-core fiber using a laser light and multi-mode fiber using an LED light.
• Single-mode fiber is more expensive but can transmit data over longer distances, while multi-mode fiber is cheaper but limited to shorter distances.

Full and Half Duplex

• Full duplex devices can send and receive data simultaneously, while half duplex devices can only do one at a time.
• Dual core fiber is full duplex, while single core fiber is half duplex.

Fiber Connectors

• Fiber cables have connectors, with LC and SC being the most common in data networking.
• Transceivers can be used to connect different types of cables, such as single-mode and multi-mode fiber.

Wireless Networking (Wi-Fi)

• Wi-Fi uses radio waves to format and encode information, with access points connecting devices to the wired network.
• Wi-Fi operates under the IEEE 802.11 standard, not the Ethernet standard.

Network Addressing

• Devices on a network have two addresses: IP addresses and MAC addresses.
• MAC addresses are permanent, unique, and assigned by the manufacturer, used for communication within a LAN segment.
• IP addresses are chosen by network administrators, used for communication between LAN segments, and can be used to access hosts on different networks.

How Routers Handle MAC Addresses

• When a message is sent, the router adds its own MAC address to the message and sends it.
• The router receives the message, strips its own MAC address off, and replaces it with the printer's MAC address.
• The router then forwards the message to the printer.

Key Facts about MAC and IP Addresses

• Hosts have both a MAC address and an IP address.
• A MAC address is used only within a Local Area Network (LAN) segment.
• An IP address can be used within a LAN segment, but it's also used to pass traffic to a different LAN segment.

MAC Addresses and Devices

• Computers and devices have MAC addresses.
• A device may have more than one MAC address.