I built the classic setup in the lab: two switches with two cables between them. Before configuring anything, spanning tree put one of the ports into blocking — makes sense, it's preventing a loop.
Then I bundled the two ports into an EtherChannel (channel-group 1 mode active on both sides) and suddenly both links are forwarding and STP isn't blocking either one. Aggregate throughput doubled.
What I don't get: the physical loop is still there — two cables between the same two switches. So why doesn't STP block one member like it did before? How does bundling make a genuine parallel path suddenly loop-safe? And is LACP doing something special here, or is it just about how STP views the port-channel?
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.
I have a network with redundant links between switches and STP is blocking ports I need. I understand STP prevents loops but how do I control which ports get blocked? How do I check which switch is the root bridge? And should I use portfast on access ports?
I'm studying VLANs and I understand what a VLAN is, but the difference between trunk and access ports confuses me. When do I use each one? And what's this native VLAN thing? Why does it matter? A plain English explanation would be amazing.
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