What's the point of VLANs if everything works without them?
Yaron · posted · 118 views
I built a network in the lab with multiple PCs and switches and everything pings fine without VLANs. So why bother? What real problem do VLANs solve? My instructor says they're essential but I don't see why when the flat network already works.
- Without VLANs, every device is in one broadcast domain. One PC sending an ARP request hits EVERY device on the network. With 500 devices that's a huge amount of broadcast traffic eating bandwidth. VLANs segment the network so broadcasts stay within their VLAN. — NivSa,
- Security too. Put your servers on VLAN 100, printers on VLAN 200, guest WiFi on VLAN 300. Now you can use ACLs between them to control who reaches what. Without VLANs, any device can talk to any other device directly at Layer 2 — there's no way to filter. — 22maya2n2,
- Try building a flat network with 10 PCs in the lab here, then ping and watch the broadcast traffic in the capture tab. Then add VLANs and see the difference — broadcasts stay contained. It's very visual and makes the point immediately. — ben31833,
- The broadcast domain argument convinced me. I didn't realize every ARP request hits every device in a flat network. With 500 hosts that's constant noise. VLANs suddenly make a lot more sense when you think about scale. — Yaron,
- Great idea. I built a 10-PC flat network, ran a ping and watched the capture tab flood with broadcasts. Then I split them into 2 VLANs and the broadcast traffic dropped by half immediately. Actually seeing it made the concept stick way better than reading about it. — Yaron,
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