Introduction to LANs If you’ve ever connected a laptop to a Wi-Fi router at home, plugged a PC into a wall port at the office, or watched Netflix on your phone over your home network — you’ve used a LAN. You just didn’t think about it that way. Most people don’t, and that’s fine. But […]
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Switches are simple devices at heart — they forward frames based on MAC addresses and keep everything connected. Add a second cable between two switches for redundancy, and suddenly you have a problem that can bring down your entire network in seconds. Spanning Tree Protocol exists precisely to solve this problem, and understanding it is
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In this lesson I will explain how PVST+ works and how Cisco switches use it to build a separate loop-free topology for every VLAN. Why Do We Need PVST+? Before we talk about PVST+, let me remind you why we have Spanning Tree Protocol at all. When you connect switches together with redundant links —
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Most people encounter EtherChannels in their Layer 2 form — bundled trunk links carrying VLANs between switches. But there’s another variation that doesn’t get as much attention: the Layer 3 EtherChannel. If you’ve already worked through “EtherChannels“, this is the natural next step. You’ll see how to take that same link-bundling concept and apply it
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Two switches. Four cables running between them. Spanning Tree blocking half of those links. Sound familiar? If you’ve ever looked at a network diagram and thought “there must be a better way,” EtherChannel is that better way. EtherChannel — also called link aggregation — takes multiple physical connections between two switches and merges them into
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Most office desks have both a computer and an IP phone sitting side by side. Both devices use standard Ethernet and UTP cables, which immediately raises a practical question — how do you connect them to the network without wasting ports or running extra cable? The Problem with Two Cables The obvious approach is to
When 802.1Q trunking carries traffic between switches, it tags Ethernet frames with a VLAN identifier so the receiving switch knows which VLAN that traffic belongs to. But there’s one special exception to this tagging rule — and that exception is the native VLAN. Understanding the native VLAN is something every CCNA candidate needs to get
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Cisco switches have a built-in ability to negotiate whether a link between two switches should operate as a trunk or a regular access port. This negotiation happens through a Cisco proprietary protocol called the Dynamic Trunking Protocol (DTP). While this sounds convenient — no manual trunk configuration required — it comes with a significant security
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Managing VLANs across a large network is one of those tasks that sounds simple until you’re sitting in front of 20 switches and realize every VLAN needs to be created on every single one of them. That’s where VTP — the VLAN Trunking Protocol — comes in. VTP allows you to create, modify, or delete
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In switched networks, connecting multiple VLANs across devices often requires efficient links that can handle traffic from different segments without needing a separate cable for each one. A trunk port serves this role by allowing frames from various VLANs to travel over a single connection, using tagging to keep them separated. Cisco switches support this
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