Introduction to Networking - Week 1

Vocabulary flashcards covering Week 1 networking concepts including devices, addressing, topologies, basic paths, and troubleshooting steps.

Network

A group of devices that can communicate and share resources.

LAN (Local Area Network)

A network operating within a local area, such as a home, lab, or office.

WAN (Wide Area Network)

A network that connects distant networks across larger geographical areas.

Internet

A global network of networks.

Endpoint / Host

A device on the network that sends or receives data.

NIC (Network Interface Card)

A hardware component that connects a device to the network.

Switch

A device that connects devices within a network.

Router

A device that connects different networks together.

Access Point

A network device that provides wireless access to the LAN.

Firewall

A network security device that controls which traffic is permitted.

Modem / ONT

A device that connects a local network to ISP access technology.

Server

A network entity that provides a service or resource to clients.

MAC Address

A Layer 2 address representing the local interface identity.

IP Address

A Layer 3 logical network address used to identify devices across networks.

Default Gateway

The router address where remote network traffic is sent.

DNS

Domain Name System, which turns human-readable names into IP addresses (e.g., google.com → IP).

STAR Topology

A common Ethernet LAN topology organized around a central device.

BUS Topology

A historically important network topology based on a shared medium.

RING Topology

A network topology arranged in a loop/ring structure where each node has neighbors.

MESH Topology

A network topology featuring multiple paths to provide connection redundancy.

Subnet Mask

A 32-bit mask used to separate network and host portions of an IP address, such as 255.255.255.0.

Troubleshooting Step 1: DEFINE

The first step in network troubleshooting: asking what you are trying to do.

Troubleshooting Step 2: OBSERVE

The second step in network troubleshooting: identifying what you know and what changed.

Troubleshooting Step 3: TEST

The third step in network troubleshooting: changing exactly one thing at a time.

Troubleshooting Step 4: LEARN

The fourth step in network troubleshooting: determining what the test result tells you.

Troubleshooting Step 5: REPEAT

The fifth step in network troubleshooting: using evidence rather than guesses to proceed.

Networking Definition

Learning the job of every box and what happens to the data as it moves between them.

Primary Purpose of a Switch

Connects devices inside the same network (e.g., PCs, printers, APs, servers).

Primary Purpose of a Router

Connects one network to another network (e.g., LAN → other LANs → Internet).

Basic Data Path Sequence

Laptop → Access Point → Switch → Router → ISP → Internet → Server.

ISP

Internet Service Provider, which links local routers to distant global networks.

OSI Model

An upcoming conceptual networking framework used to understand protocol layers.

TCP/IP

The standard protocol suite used for interconnecting network devices on the Internet.

Encapsulation

The process of wrapping data with headers as it moves down through network layers.

PDU

Protocol Data Unit, representing a specific block of data at a given layer.

Wireshark

A software application used for analyzing network traffic and inspecting packets.

Layer 2

The Data Link Layer associated with local interface identity (MAC ADDRESS).

Layer 3

The Network Layer associated with logical network addresses (IP ADDRESS).

Ping Command

A network command line utility used to test connectivity between hosts.

Packet Tracer

A simulation program used to build, configure, and test network setups.

Packet Tracer Challenge #1 Setup

Connecting two PCs to one switch to enable direct communication on the same network.

PC 1 Initial IP Address

192.168.1.10 assigned during Packet Tracer Challenge #1.

PC 2 Initial IP Address

192.168.1.20, which allowed successful pinging from PC 1 on the same subnet.

PC 2 Modified IP Address

192.168.2.20, which placed PC 2 on a different network and broke direct ping connectivity without a router.

Key Question for Network Device Choice

Are we connecting DEVICES — or connecting NETWORKS?

Today's Big Question

What has to happen between your laptop and Google for a web page to appear?

Name-to-Connection Step 1

You enter google.com in the browser.

Name-to-Connection Step 3

The host decides whether the destination is local or remote.

Mental Model of Network Journey

HOST → SWITCH → ROUTER → INTERNET → ROUTER → SWITCH → HOST.

Core Principle of Network Troubleshooting

Do not guess randomly; change one thing, test, observe, and use evidence.