The World of Computer Networking. Your CCNA starts here

Explore how network devices communicate and form a computer network, compare TCP/IP and ACI models, and learn through Wireshark-based practice how protocols interact under the hood.

Install and use Wireshark to capture and analyze packets from your computer, filter TCP traffic, inspect IP, TCP, TLS, DNS, and MAC addresses, and relate them to the TCP/IP model.

Learn why computer networks are needed to send and receive data. Explore how applications use protocols like http, https, smtp, and ftp to talk across tcp/ip.

Explore the tcp/ip model's four layers - application, transport, internet, network access - and compare tcp vs udp, and how protocols like http, dns, ip4/6, icmp enable end-to-end communication.

Map captured packet data to the TCP/IP model's four layers—application, transport, internet, and network access—using Wireshark, with examples like TCP, UDP, DNS, and the OSI model.

Explore how bits are the smallest information unit and how media transmit binary digits as light or waves, with Unicode encoding and IP version four using bytes or four octets.

Compare OSI and TCP/IP models, map layers, and explain that IPsec spans multiple layers; describe how application, transport, network, and network access correspond and encapsulation and decapsulation concepts.

Explain how data is encapsulated with headers at each layer—from application to physical—and later decapsulated at the receiver, highlighting layer independence and the role of pdus.

Learn why Ethernet dominates the data link and physical layers in the TCP/IP model, and explore how wired and wireless media enable data transfer.

Explore ethernet as a family of IEEE standards for data link and physical layers, including 802.3 for wired and 802.11 wireless, and why devices must follow these protocols to communicate.

Explore copper, fiber, and wireless media in Ethernet networks, comparing twisted-pair copper, single- and multi-mode fiber, and IEEE 802.11 standards, with their speeds, distances, and trade-offs.

Learn how network interface cards enable wired and wireless connectivity across devices, from internal and external NICs to switches and access points, each NIC carrying a unique MAC address.

Learn how mac addresses are the unique hardware identifiers built into every nic, formatted as six colon-separated hex pairs, required for communication over copper, fiber, or wireless.

Compare binary and hexadecimal, noting that hex uses 16 characters and four bits per character. Discover why hex is shorter and how a 48-bit mac address has two parts.

Explain the structure of the mac address, a 48-bit identifier in six octets, with an IEEE-assigned OUI and a NIC-specific segment for unique devices.

Mac addresses are 48 bits, with a 24-bit vendor-specific oui and a 24-bit network interface card specific portion, commonly shown as six two-hex-character groups separated by colons.

Explore bandwidth as the maximum bits per second a link can carry and identify a bottleneck along the path, from copper to fiber, spanning kbps to 100 gigabits per second.

Explore throughput as the actual data that passes over a link after header overhead from the tcp/ip layers, showing how it differs from bandwidth.

Explore how throughput falls short of bandwidth, illustrated by real-world speed tests on speedtest.net showing download and upload rates below a 100 mbps link, and learn about latency and ping.

Analyze latency as the one-way delay in real-time networks. Examine queuing, processing, transmission, and propagation delays across routers and switches as measured at the application layer.

Explore latency, learn about round trip time (RTT) or ping, and measure RTT with the built-in terminal to understand real-time app performance.

Learn to measure round-trip time (RTT) between your computer and a remote server using the ping utility in a terminal, using 8.8.8.8 and observing RTTs around 16–24 ms.

Explore jitter as variable latency in packet delivery, how differing delays cause out-of-order arrivals, TCP reordering, and potential video or voice disruption, especially under congestion.

Explore the packet loss rate as a key network property alongside bandwidth and jitter, showing 0% loss versus simulated loss and how TCP or applications recover lost packets, protecting throughput.

Explore bandwidth, throughput, latency, rtt (ping), and jitter to understand their impact on network performance and when high jitter prompts redesign.

Explore the network switch, a device on the physical and data link layers, that uses frames and bits across end-user and uplink ports, with copper and fiber options.

Network switches operate on the physical and data link layers to transfer frames between devices, using a per-port MAC address table to forward frames efficiently while ignoring IP addresses.

Explore the ethernet frame header according to IEEE 802.3, including preamble and SFD. Understand destination and source MAC addresses, VLAN tags, type, payload, and CRC.

Explore unicast, multicast, and broadcast as the core types of communication across data link and other layers, with examples of sending to a single device, a group, or all devices.

Explore unicast, multicast, and broadcast mac addresses at the data link layer of tcp/ip model, including how unicast addresses are assigned and mapped by switches, and how multicast saves bandwidth.

Explain full duplex: simultaneous send and receive on a link using separate channels, such as fiber, copper, or wireless; contrast half duplex, where only one device transmits at a time.

Explore how half-duplex networks experience collisions when two devices transmit simultaneously, causing overlapping signals in wireless and copper media, while fiber remains full duplex, with Ethernet standards governing collision handling.

Explore collision handling mechanisms in wired and wireless networks, including Csma CD with collision detection and Csma CA with collision avoidance.

Explore collision domains across hubs, switches, and wireless access points, and explain how collision detection and collision avoidance limit collisions on half duplex links.

Explore how devices negotiate speed and duplex across copper and fiber links, why full duplex outperforms half duplex, and how switches shape collision domains for optimal network performance.

Analyze ethernet headers with Wireshark, focusing on destination and source mac addresses and the type field; learn how unicast, multicast, or broadcast are indicated and ip version four uses 0800.

Explore how ethernet frames use broadcast destinations to reach all devices, contrast with unicast sources, and observe Dhcp and ARP broadcast traffic during live packet capture.

Explore Ethernet fundamentals across the data link and physical layers, including MAC addresses, NICs, Ethernet frame structure, switches, collision domains, and CSMA/CD and CSMA/CA mechanisms.

Explore the network layer by learning why IP addresses matter, the purpose of routers, how routers find optimal paths to networks, and how they route different packets.

Examine how switched networks flood broadcast frames, causing broadcast storms, and how large mac address tables and routers interconnect networks at the network layer using IP addresses.

Define an ip address as a logical network-layer address, often assigned by dhcp, that may change across networks, while mac addresses are hardware identifiers assigned by manufacturers.

The lecture explains IPv4 versus IPv6 addresses on the TCP/IP network layer. IPv4 uses decimal four-number format, while IPv6 employs 128-bit hexadecimal with eight sections.

Explore how IPv4 uses four octets, eight bits each, for a 32-bit address (0–255) and why NAT and private and public address spaces address its 4.3 billion limit.

Understand how mac addresses differ from ip addresses: macs include an organizationally unique identifier, while ipv4 addresses are 32-bit dotted decimals that must share a network in a switched network.

Explore unicast, multicast, and broadcast IPv4 addresses, their 1-to-1 and group communications, and how broadcast targets all devices on the same switched network.

Explore how routers route IP packets on the network layer, manage ports with MAC and IP addresses, and use routing protocols to build routing tables and forward packets.

Explore how routers operate on the network layer to route IP packets and build routing tables, and distinguish LANs under common administration from WANs that interconnect multiple networks.

Explore how routers interconnect LANs to form the internet, with switches at the data link layer, private ip addresses and mac addresses, and default gateways for internet access.

Explore IP addressing on the network layer, router roles, and the five IP classes (A–E) with ranges, masks, and private versus public use, noting 127 is reserved for loopback.

Explore the localhost loopback address 127.0.0.1 and its independence from network connections. Verify network stack on any device and access services running locally, even when the network adapter is disabled.

Explore localhost and loopback 127.0.0.1 to run local services, such as a web server with nginx via docker. Learn the difference between private and public IP addresses.

Explain private vs public IP addresses and why private addresses are not routable on the global internet, and how NAT enables private networks to access web resources.

Lecture defines network as a group of devices that communicate via switches and explains how a network prefix and mask split IPs into network and host parts, including private ranges.

Private ip address ranges include class a 10.0.0.0/8, class b 172.16.0.0/12, and class c 192.168.0.0/16, with examples like 192.168.1.0/24. These addresses are not routable and reusable.

Learn how public IP address ranges, not private, are routable on the internet and assigned by RIPE and charged for; verify ownership via 8.8.8.8 and 8.8.8.0/24.

Explore the difference between static and dynamic IP addresses and learn why static IPs are convenient for web and email services, with permanent DNS mappings and security considerations.

Discover how dynamic IP addresses are assigned by a DHCP server, the benefits of cheaper, more private addresses, and how dynamic DNS updates hostname mappings while noting DNS delays.

Learn how dhcp assigns ip addresses and how to switch to a static ip, including dns settings, default router, and subnet mask, and why reconnecting may return the same address.

Describe the ipv4 header structure, from the minimal 20-byte header to fields like version, ihl, dssp, eqn, ttl, protocol, checksum, and the source/destination addresses with optional options and payload.

Analyze the IPv4 header fields in Wireshark, including version, header length, DSCP/ECN, total length, identification and fragmentation flags, TTL, protocol, header checksum, and source and destination addresses.

Analyze DHCP request and response packets, inspect IPv4 header fields and fragmentation, compare TTL values, and observe UDP and ARP interactions during DHCP discovery and server responses.

Explore the network layer basics, including IP addresses, IPv4 vs IPv6, and the roles of routers, with emphasis on private vs public addresses and subnetting foundations.

Explore subnetting and network masks, revisit the network definition with prefix and mask, and learn how the mask defines network and host parts and IP addresses.

Explore how a network is defined by its prefix and mask, using a /8 (255.0.0.0) example. Learn network address, broadcast address, and host addresses within 10.0.0.0/8, including reserved addresses.

Work through a mini challenge to identify the network address, broadcast address, and a valid host address for a given network prefix with 16-bit host part, using 172.19.0.0 to 172.19.255.255.

Examine a /24 private ip network to identify its network, broadcast, and host addresses, verify them with ping, and perform binary to decimal conversions.

Master binary math by converting eight-bit binary numbers to decimal and back, with practical examples and powers of two, tailored for IPv4 addresses and subnetting basics.

Learn to convert decimal to binary by comparing powers of two, deducting, and setting bits left to right, then perform binary to decimal conversion and explore and/or operators.

Explore bitwise math by applying the and and or operators to 4-bit numbers, yielding 0010 and 1011, and relate these to mask representations in IP v4 addresses.