Chapter 1 of 6 · Cisco CCNA 200-301

Network Fundamentals

Devices, topologies, cabling, TCP and UDP, IPv4, IPv6, wireless, virtualization and switching.

  • 17topics
  • 1 h 30 minfast track
  • 2diagrams and exhibits
  • 20%of the exam
Start with Network Components and Their Roles

Topics in this chapter

Take them in order, or jump to the one you need.

  1. 1Network Components and Their RolesLearn what routers, switches, firewalls, IPS, access points, controllers, endpoints, servers and PoE do in a network and how each…6 min
  2. 2Network Topology ArchitecturesCompare two-tier, three-tier and spine-leaf designs, plus WAN, SOHO, on-premises and cloud networks, and learn where each design…Diagram6 min
  3. 3Physical Interfaces and Cabling TypesCompare copper, multimode fiber and single-mode fiber, understand shared media versus point-to-point Ethernet, and see how PoE…5 min
  4. 4Interface and Cable IssuesDiagnose interface and cable problems on a Cisco switch or router, including collisions, CRC errors, runts, giants, and speed or…6 min
  5. 5Comparing TCP and UDPCompare TCP and UDP, including the three-way handshake, reliability, windowing, headers, port numbers and which applications use…5 min
  6. 6IPv4 Addressing and SubnettingLearn how IPv4 addresses and masks work, how to find the network, broadcast and usable host range of a subnet, and how to…6 min
  7. 7The Need for Private IPv4 AddressingLearn why private IPv4 ranges exist, the three RFC 1918 blocks, how they relate to NAT and address exhaustion, and which special…6 min
  8. 8IPv6 Addressing and PrefixesLearn how IPv6 addresses are written and shortened, how prefixes work, and how to configure and verify IPv6 addressing on a Cisco…6 min
  9. 9IPv6 Address TypesCompare IPv6 global unicast, unique local, link-local, anycast and multicast addresses, and learn how the modified EUI-64 method…5 min
  10. 10Verifying IP Parameters on Client Operating SystemsCheck a client IP address, mask, gateway and DNS on Windows, macOS and Linux with the right commands, and learn how to read the…5 min
  11. 11Wireless PrinciplesUnderstand Wi-Fi basics including SSIDs, 2.4 and 5 GHz bands, non-overlapping channels, RF signal terms and the encryption…5 min
  12. 12Virtualization FundamentalsLearn how server virtualization, hypervisors, containers and VRFs work, how a VM differs from a container, and how a router keeps…5 min
  13. 13Switching ConceptsLearn how a switch builds its MAC address table, learns and ages addresses, forwards known frames and floods unknown unicast and…5 min
  14. 14IPv4 Subnetting Practice: Find the SubnetFive worked IPv4 subnetting problems with every step shown: find the network, broadcast and host range, cross octet boundaries…5 min
  15. 15VLSM and Address Planning PracticeWorked practice: choose a prefix from a host count, split a /24 evenly, plan variable length subnets and write ACL wildcard…4 min
  16. 16IPv6 Addressing Practice: Shorten, Expand and SubnetWorked IPv6 addressing problems with steps: shorten and expand addresses, spot invalid ones, count subnets in a /48 and place an…5 min
  17. 17IPv6 Address Types and EUI-64 PracticeWorked practice for recognising IPv6 address types from their first digits and building interface IDs with EUI-64, link-local and…5 min

About this chapter

What this chapter covers

Network Fundamentals is where the CCNA begins, and it describes what a network is made of.

It covers the basic rules that make a network work. Almost every later chapter builds on it, so a weak spot here tends to show up again elsewhere.

The chapter follows domain 1.0 of the Cisco CCNA 200-301 version 1.1 exam topics. It has thirteen published objectives, and each gets its own page.

Weight in the exam

Domain 1.0 carries about 20 percent of the published exam objectives, which makes it one of the larger domains.

It is also the broadest one in the exam. The topics range from physical cables to addressing maths to wireless radio, so it helps to study it in small steps.

Note

Subnetting and IPv6 reward practice, so plan extra worked examples for those pages.

How the topics fit together

The pages move from the physical network up to the logical one.

Partscomponents and topologyLinkscabling and interface issuesData movementTCP, UDP and switchingAddressingIPv4 and IPv6

First come the parts of a network. The components page describes routers, switches, firewalls, access points and controllers. The topology page shows how they are arranged in campus, data centre, WAN and cloud designs.

The cabling and interface pages cover what connects them and how to spot a faulty link.

Next comes how data moves. TCP and UDP explain how applications send data end to end. Switching concepts explain how a switch forwards frames inside a network.

Then comes addressing. IPv4 addressing and subnetting teach you to carve up address space, and the private addressing page explains why that space is limited. IPv6 is covered in two parts: how addresses are written and configured, and what the different address types mean.

A page on client operating systems shows how to check addressing on real computers.

The last pages cover two broader ideas. Wireless principles explain how Wi-Fi works over radio. Virtualization shows how servers, applications and routing tables can be shared on common hardware.

How to use these pages

Every topic page has the same five-part shape, so you always know where to look.

  • What it is
  • How it works
  • What to remember for the exam
  • Common mistakes
  • Check yourself

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