200-301 cheat sheet

Exam at a glance

Domain weightings

How much of the exam each domain covers. Spend your study time in proportion — the heavier the domain, the more questions you'll see.

Key terms

OSPF

OSPF (Open Shortest Path First) is a link-state interior gateway routing protocol that builds a topology map and computes shortest paths by cost. CCNA requires configuring and verifying single-area OSPFv2, including router IDs, neighbor adjacencies, and network types.

VLAN

A VLAN (Virtual Local Area Network) is a logical segmentation of a switched network that groups ports independently of physical location. CCNA covers configuring normal-range VLANs across multiple switches and carrying them over 802.1Q trunks.

Trunking

Trunking is the practice of carrying traffic for multiple VLANs over a single switch link using 802.1Q tagging. A trunk adds a VLAN tag to each frame so the receiving switch can place it in the correct VLAN; the native VLAN is sent untagged.

Spanning Tree Protocol

The Spanning Tree Protocol (STP) is a Layer 2 protocol that prevents switching loops by electing a root bridge and blocking redundant paths. CCNA focuses on interpreting Rapid PVST+ operations such as port roles and states.

EtherChannel

EtherChannel is a technology that bundles several physical switch links into one logical link for greater bandwidth and redundancy. CCNA covers configuring Layer 2 and Layer 3 EtherChannel using LACP.

Subnetting

Subnetting is the practice of dividing an IPv4 network into smaller subnetworks using a subnet mask or CIDR prefix. It is one of the most heavily tested CCNA skills, requiring fast calculation of network, host, and broadcast addresses.

Private IPv4 Addressing

Private IPv4 addressing is the use of the RFC 1918 ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) that are not routable on the public internet. Devices using private addresses reach the internet through NAT.

NAT

NAT (Network Address Translation) is a technique that maps private IP addresses to public addresses at a router boundary. CCNA covers configuring inside source NAT with static mappings and pools, including the many-to-one PAT variant.

First Hop Redundancy Protocol

A First Hop Redundancy Protocol (FHRP) is a protocol that lets multiple routers share a virtual gateway address so hosts keep connectivity if one router fails. HSRP, VRRP, and GLBP are the common examples CCNA expects you to recognise.

Access Control List

An access control list (ACL) is an ordered set of permit and deny rules a router or switch uses to filter traffic. CCNA covers standard and extended ACLs, and every ACL ends with an implicit deny of all unmatched traffic.

AAA

AAA (authentication, authorization, and accounting) is a security framework that verifies identity, controls what a user may do, and records activity. CCNA covers AAA concepts along with device access control and RADIUS/TACACS+ at a conceptual level.

REST API

A REST API is a web interface that uses HTTP verbs (GET, POST, PUT, DELETE) to perform CRUD operations on resources, commonly exchanging JSON data. CCNA's automation domain expects you to recognise REST characteristics, authentication types, and JSON structure.

JSON

JSON (JavaScript Object Notation) is a lightweight, human-readable data format that represents data as key-value pairs, arrays, and nested objects. CCNA's automation domain expects you to recognise valid JSON structure and its components.