Network Hardware

🌐 Network Hardware

📌 Introduction

Basic Definition:

• Even if two computers are connected via Wi-Fi ad hoc mode, technically that’s still a network. But typically, networks are more complex.

Every device on a network is called a “node”.

• Every node must have a network address — without it, communication isn’t possible.

LAN Example (Ref: Figure 1):

• A star topology setup with:
  • 5 Computers (Windows, macOS, Ubuntu, etc.)
  • 1 Central Switch
  • 1 Network Printer (connected directly to the switch)
  • 1 Local Printer (connected directly to a specific computer)
  • 1 Scanner
  • 1 Windows Server

Printer Types:

• 🖨 Network Printer → Connected directly to the switch; accessible by all devices on the network.
• 🖨 Local Printer → Connected to a single computer; not directly accessible by others on the network.

💡 Handy Tips:

• Star topology: All devices are connected to a central switch.
• Local printer = Like homemade tea. Only the one who made it can enjoy.
• Network printer = Like an office coffee machine. Everyone can use it 😎

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🧠 LANs and Network Hardware

💡 Networking Analogy:

• Applications/data = traffic or payload on the network.
• OS = traffic controller.
• Hardware & cabling = road system on which data travels.
• Physical topology = layout of hardware + cables.

🌐 LAN (Local Area Network):

• Covers a small physical location like an office or building.
• Each node can communicate directly with others.
• Example (Figure 1-7): 5 computers, a network printer, a local printer, a scanner, and a switch — all connected via wired connections.

🔁 Switch:

• Receives data on one port and forwards it to the correct port.
• Efficient: sends data only to the target device, unlike old hubs which broadcasted to all.
• Central switch-based layout = star topology.

🧱 Hubs (Old Tech):

• Broadcasted data to all devices.
• Replaced by switches, which are more efficient and reduce traffic.
• The term “hub” is still used generically for central devices.

🔌 Network Ports & NICs:

• Network port = where the cable plugs in.
• Types:
  • Onboard port → built into the motherboard (Figure 1-9).
  • Modular NIC → plugs into an expansion slot (Figure 1-10).
• Both types are generally referred to as NICs (Network Interface Cards).

🕸 Topologies:

1. Star Topology:
   • All devices connected to a central switch.
   • Most common layout in LANs.
2. Mesh Topology (Ref: Figure 1-1):
   • Each device is directly linked to every other device.
   • Highly redundant, but complex.
3. Bus Topology:
   • Devices are connected in a line (like daisy-chained switches).
   • Backbone = main high-speed data path linking segments.
4. Hybrid Topology (Ref: Figure 1-11):
   • Combination of topologies (e.g., switches in a star, but those switches linked in a bus).
   • Real-world networks are often hybrid.

1. Hub-and-Spoke Topology (Ref: Figure 1-12):
   • Central switch = hub.
   • Peripheral switches = spokes.
   • Each spoke has its own computers → overall structure is a centralized but distributed network.

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🧠 Routers and LANs

🌍 Main Role of a Router:

• Acts as a bridge/gatekeeper between different networks.
• Routes traffic from one network to another (e.g., LAN to Internet).
• Chooses the best path for data transmission.

🏠 SOHO Networks (Small Office/Home Office):

• Typically ≤10 devices.
• Use all-in-one consumer-grade router:
  • Combines router + switch + Wi-Fi access point.
  • Has multiple LAN ports + 1 WAN port (for ISP connection).

🔎 Note (Figure 1-10):

• Combo devices are integrated solutions.
• Don’t confuse them with enterprise routers, where each port may link to a different LAN.

🔁 Switch vs Router:

Feature	Switch	Router
Function	Connects devices within one LAN	Connects multiple LANs/networks
Number of LANs	Just one	Multiple
Traffic handling	Based on MAC addresses (local)	Based on IP addresses (network-level)
Acts as a gateway?	No	Yes

🧠 Memory Aid:

“Switch manages internal communication, router connects to the outside world.”

1. 🏢 Enterprise Router Example (Figure 1-14):
   • A single router connects to 3 different LANs.
   • Each LAN has a separate IP/interface.
   • The router is a multi-homed device (has multiple IP addresses).

1. 🚪 Gateway Role:
   • The router serves as a gateway between networks.
   • Without a router, devices on different LANs can’t communicate.

🧑‍💻 Node vs Host:

Term	Definition	Example
Node	Any network-connected device	Computer, router, switch
Host	A node that provides or accesses resources	Computer, printer, server
End Device	Cisco term for hosts	Smartphone, laptop, printer
Intermediary Device	Cisco term for networking equipment	Switch, router, firewall

💡 Key Difference:

• Every host is a node, but not every node is a host.

🧵 Quick Recap:

• Router connects different networks.
• Switch connects devices within one network.
• Hosts are end devices that provide or use resources.
• Nodes include all devices connected to a network.
• Router = gateway, especially for LAN-to-Internet communication.
• Combo device = great for SOHO setups (router + switch + Wi-Fi).

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🧠 Network Types – MANs, WANs, PANs, etc.

📌 1. Overview of Network Types:

Type	Description	Typical Range	Example
PAN (Personal Area Network)	Connects personal devices	A few inches to feet	Smartphone ↔ Laptop
BAN (Body Area Network)	Wearables & biometric devices	Around the human body	Smartwatch, AR glasses
LAN (Local Area Network)	High-speed in a small area	Room or building	Office PCs with a switch
CAN (Campus Area Network)	Multiple LANs in one area	College or corporate campus	Library + Admin LAN
MAN (Metropolitan Area Network)	Covers a city or metro area	City-scale	Govt buildings across a city
WAN (Wide Area Network)	Connects distant networks	National or global	Office in SF ↔ Office in London
SAN (Storage Area Network)	Dedicated network for data storage	Data center	Bank storage systems

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📌 2. Key Notes:

• ✅ WAN covers large distances; Internet is the largest WAN.
• ✅ MAN and CAN can sometimes be used interchangeably.
• ✅ WAN links are typically provided by third-party ISPs.
• ✅ PANs and BANs are personal-scale and mostly wireless.
• ✅ WLAN = wireless version of LAN (e.g., Wi-Fi at home).

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📌 3. Visual Size Hierarchy (Figure 1-16 idea):

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PAN  <  LAN  <  CAN ≈ MAN  <  WAN
         ↑            ↑
     Home use      City scale

• PAN ≈ Personal bubble
• LAN ≈ Room or building
• MAN/CAN ≈ Campus or city
• WAN ≈ Country to global

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📌 4. Key Examples:

• PAN: Connecting smartphone to wireless headphones.
• BAN: Smartwatch + fitness tracker + AR glasses.
• LAN: Office with 5 computers linked via a switch.
• CAN: University network with admin, labs, library.
• MAN: Government offices in a city connected via fiber.
• WAN: Company HQ in Mumbai linked to branch in London.
• SAN: Backend data network in a bank’s server room.

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📌 5. Summary Line:

“The bigger the area a network covers, the bigger its name!”

PAN → LAN → MAN/CAN → WAN (SAN & BAN are special-use networks)

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