The networking folks at work have never been able to explain to me quite what a vlan is. I understand it to be a tag you can put on a packet so you can segment your network by allowing which tags can access which ports/routes. Am I thinking in the right direction? - ThreadSky

toonspin.nl • 60 days ago

The networking folks at work have never been able to explain to me quite what a vlan is. I understand it to be a tag you can put on a packet so you can segment your network by allowing which tags can access which ports/routes. Am I thinking in the right direction?

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michael.bonnettjr.com•60 days ago

Yeah, that's a pretty good way to think about it. Technically speaking, the VLAN tag (aka the IEEE 802.1Q tag) is added to the Ethernet frame and not the IP packet. Since Ethernet is an L2 standard, VLAN management is often handled by switches. They control which VLANs can cross L2 trunks.

toonspin.nl•59 days ago

Is a vlan one of those terms that can be different things, like eg server? Is a vlan the lil tag you can make rules for, and also the general concept of the partition/segment of your network that you create with those?

michael.bonnettjr.com•59 days ago

Yes, depending on the context, "VLAN" might refer to:

1. The concept of segmenting a physical Layer 2 network into virtual Layer 2 networks
2. A specific instance of a virtual Layer 2 network
3. The 802.1Q tag added to an Ethernet frame

Like most things in networking, it's kind of confusing.

tracketpacer.bsky.social•59 days ago

but those are all basically the same thing, yeah? i.e. you achieve a layer 2 segment with the VLAN ID tags

michael.bonnettjr.com•59 days ago

Exactly 👍

toonspin.nl•59 days ago

I think what was confusing me is that the term "vlan" gets muddled in common parlance. At least where I've worked so far - and again I don't have a background in networking. But for me it was like, is it a subnet, is it a tag, is it a route... But I think I'm grokking the concept now.

toonspin.nl•59 days ago

Thanks Michael & Tracket!

listerthrawn.bsky.social•58 days ago

I know why you're confused. It's because all of these terms in a lot of implementations refer to the same separation. So one subnet is assigned to one vlan with one route (the router may even be the same device as the switch). But you can put 2 subnets on a vlan (not saying you should).

shatter.bsky.social•59 days ago

Hashtags for packets.

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