VLAN Cheatsheet — Cisco CCNA Fundamentals

This VLAN cheatsheet provides a clear and structured overview of essential VLAN concepts for learners preparing for the Cisco CCNA certification. It summarizes the core principles of VLAN segmentation and offers a visual reference to support lab work and exam preparation. Included topics: • VLAN segmentation and trunking illustrated through a simple topology • Default VLAN behavior and VLAN ID ranges • Configuration steps for VLAN creation and assigning access ports • 802.1Q trunking, native VLAN configuration, and allowed VLAN lists • Voice VLAN behavior using CDP advertisement • DTP operating modes with an interaction matrix • VTP modes and their operational characteristics • Key verification and troubleshooting commands (show vlan, show interfaces trunk, reset commands) The cheatsheet is designed as a compact visual reference to help students understand how VLANs operate in real lab environments such as Packet Tracer, EVE-NG, and GNS3. It focuses on accuracy, clarity, and alignment with CCNA fundamentals. Additional learning resources are available at https://pingmynetwork.com/network/concepts/vlan-fundamentals本VLAN（Virtual Local Area Network，虚拟局域网）速查表为备考思科CCNA（Cisco Certified Network Associate）认证的学习者提供了清晰且结构化的核心VLAN概念总览。 它梳理了VLAN分段的核心原理，并提供可视化参考资料，以辅助实验操作与备考复习。 包含以下主题： • 基于简易拓扑图示的VLAN分段与干道（trunking）技术 • 默认VLAN工作行为与VLAN ID范围 • VLAN创建及访问端口分配的配置步骤 • 802.1Q干道协议、本征VLAN（native VLAN）配置与允许VLAN列表 • 依托CDP（Cisco Discovery Protocol，思科发现协议）通告的语音VLAN工作机制 • DTP（Dynamic Trunking Protocol，动态干道协议）工作模式及交互矩阵 • VTP（VLAN Trunking Protocol，VLAN干道协议）模式及其运行特性 • 核心验证与排障命令（如show vlan、show interfaces trunk、复位类命令） 本速查表设计为精简型可视化参考资料，旨在帮助学习者理解VLAN在Packet Tracer、EVE-NG及GNS3等真实实验环境中的运行逻辑，其核心追求为精准性、清晰度以及与CCNA考纲基础的高度契合。 更多学习资源可访问：https://pingmynetwork.com/network/concepts/vlan-fundamentals