> My LAN uses IP addresses.

I've never heard of a LAN without IP addresses. Is that a thing? I'd assume that no IP addresses means you can't even use TCP/IP at all, right? Is there something else you'd use instead?

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mitxela 3 hours ago | parent | next [-]

You can send packets over Ethernet, without IP. That's what people did before IP was invented and took over most networked communication. It's less convenient, because you can't reuse the IP stack, so almost nobody does.

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ButlerianJihad 3 hours ago | parent [-]

Ethernet uses frames, not packets. A falsehood that programmers believe about networking is that everything is a packet. In fact, the "PDU" or protocol data unit for each OSI layer is defined and named differently.

So Ethernet communicates with frames. You can simply send frames across a purely Ethernet network. Or, you can take a PDU from an upper layer, encapsulate it as Ethernet frame, and send it across. Most LAN protocols are flexible like that.

https://en.wikipedia.org/wiki/Frame_(networking)

https://en.wikipedia.org/wiki/Network_packet

https://en.wikipedia.org/wiki/Protocol_data_unit#Internet_pr...

And TFA provides a list of upper-layer protocols that may be encountered on a LAN today: "IP, IPX/SPX, Phase IV, AppleTalk, VINES, NetBEUI, or SNA".

NetBIOS and NetBEUI are particularly interesting here, because NetBIOS Frames did use IEEE 802.2 LLC, while NBT uses TCP/IP for NetBIOS transport.

https://en.wikipedia.org/wiki/NetBIOS

	▲	mitxela 3 hours ago \| parent [-]
		A falsehood networkers believe about programming is that you have to call things what the relevant standard calls them, and you have to obey all the random differences that come from different people writing the different standards. IP packets and Ethernet packets aren't the same thing, but IP packets and IP frames are the same thing, because packets and frames are the same thing.

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peanut-walrus 4 hours ago | parent | prev | next [-]

Quite common to run unnumbered IS-IS backbones. Whether this can rightfully be considered a "LAN" is up for debate.

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solraph 5 hours ago | parent | prev [-]

IPX/SPX is not IP based.

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LoganDark 5 hours ago | parent [-]

Can that still be used from modern operating systems? Maybe only Linux?

	▲	solraph 4 hours ago \| parent [-]
		I suspect recentish versions of Windows still have the driver available, just not installed by default. However the article is about falsehoods programmers believe about LANs. If you are writing some kind of driver and assume all traffic you receive is IP traffic and don't verify the header, you are going to have a bad time.