Cisco - Ping Labz (Page 4)

Tagged vs Untagged VLANs: How Trunks and Access Ports Really Work

Tagged and untagged frames are the half of every VLAN problem nobody explains clearly. The mental model, when each is correct, the native VLAN, and the cross-vendor (Cisco / Aruba / Juniper) cheat sheet.

7 min read Apr 25, 2026

VLAN public

VLAN Hopping Attacks Explained: Switch Spoofing and Double Tagging

J

VLAN hopping bypasses Layer 2 isolation. The two attacks (switch spoofing via DTP, double tagging via the native VLAN) and the four-line Cisco configuration that defeats both.

7 min read Apr 25, 2026

VLAN public

802.1Q VLAN Tag Explained: The 4 Bytes That Make Trunking Work

J

The 802.1Q VLAN tag is 4 bytes inserted into Ethernet frames to carry VLAN identity across trunks. TPID, TCI, PCP, DEI, VID, and the native VLAN explained byte by byte.

6 min read Apr 25, 2026

STP public

Rapid Spanning Tree Protocol (RSTP): What Changed from 802.1D STP

J

RSTP (802.1w) replaced classic 802.1D's 30-50 second convergence with sub-second failover. The five key changes that make it possible, and how to deploy Rapid PVST+ on Cisco IOS XE.

7 min read Apr 25, 2026

BGP public

BGP vs OSPF: When to Use Each Routing Protocol

J

BGP and OSPF solve different problems and almost always run together in production. The technical differences, when each is the right answer, and the architecture pattern most enterprises end up with.

7 min read Apr 25, 2026

802.1X public

Cisco ISE 802.1x Wired Configuration: A Practical Step-by-Step Guide

J

A complete, copy-pasteable walkthrough of deploying wired 802.1x with Cisco ISE as the RADIUS server and a Catalyst switch as the authenticator — from Policy Sets to IBNS 2.0 CLI to show commands and Live Logs.

12 min read Apr 20, 2026

Cisco public

Cisco SD-WAN in 2026: The Real Value Is Day-2 Operations

J

Path steering is now table stakes. Real SD-WAN value in 2026 comes from Day-2 operations: template management, observability, policy drift, and upgrade discipline. Here is what actually matters once the rollout is done.

16 min read Apr 7, 2026

Cisco public

Catalyst Center CLI Templates for Network Teams That Hate Fragile Automation

J

Catalyst Center CLI templates sit between full manual work and heavy automation frameworks. Here is how to use them for repeatable, non-fragile network changes across campus and enterprise sites without building a platform you regret in six months.

13 min read Apr 7, 2026

Cisco public

Post-Quantum Crypto in Cisco Campus Networks: What Operators Need to Know

J

NIST finalized three post-quantum cryptography standards and Cisco is marketing quantum-ready Catalyst 9000s. Here is what PQC actually means for campus networks, where your real exposure is, and what to prioritize now versus watch.

12 min read Apr 7, 2026

Cisco public

Wi-Fi 7 for Cisco Shops: Upgrade Now or Wait?

J

Wi-Fi 7 is shipping and Cisco has a full 802.11be AP lineup, but the real question is whether your environment, wiring, and refresh timing justify the spend now. A practical upgrade decision guide for wireless architects.

13 min read Apr 7, 2026

Cisco public

Catalyst Center and ThousandEyes: What Problem Does This Actually Solve?

J

Catalyst Center shows your infrastructure is healthy while the user still cannot load Salesforce. ThousandEyes closes that gap. Here is what the integration actually solves, how it works, and where it fits in a Cisco shop.

14 min read Apr 7, 2026

Cisco public

Is Cisco SD-Access Worth It in 2026? A Brownfield Reality Check

J

After years of real-world SD-Access deployments, the honest answer is: it depends. A practical, checklist-driven reality check on whether Cisco SD-Access is worth the effort in brownfield campus networks in 2026.

12 min read Apr 7, 2026