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by geofft 2725 days ago
I mean, sure, CSAIL might have been wrong. (Worth mentioning this is just a single building, not all of MIT.) But if even the MIT computer science network isn't set up "right," there's doubtless a huge amount of technical debt for everyone else who's not an MIT nerd to clean up before they can make IPv6 work. And IPv6 would have been more successful if the designers had taken that into account.
2 comments
Dylan16807 2725 days ago
The switches being good at ARP and bad at an alternative isn't down to technical merits, it's down to which one existed first.

And it sounds like turning the intelligent feature off and treating the packets as pure broadcast, just like ARP packets, would have fixed the problem. If the switch can't do that in the right way, it's not the protocol's fault.

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d00bianista 2725 days ago
Yup, turning off snooping would have fixed the issue at hand but not the poor choice of relying on STP for redundancy.

I've seen this happen a few times in my life in production systems, designed by someone else. Overload a switch somehow and it goes straight in ludacris mode because of the topology. Properly configured networks suffer minor outages only in case of single device meltdowns.

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Dylan16807 2725 days ago
It seems like it took multiple switches melting down from bad software design to cause the problems. I originally had a line about the risk of large broadcast domains but the comments on the post claim they were actually pretty small.
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d00bianista 2725 days ago
Large L2-networks never work well, they all have some issues. Their existence is purely based on lazyness or believing that Ethernet works like the water main... I admit that I might be more obsessive compulsive than most but I find reconfiguring networks to be a whole lot of fun :)

And no matter how smart the peole on campus are, there will always be someone who cannot accept that someone else is more right. I have first hand experience of this since I have tunneled IPv6 at home and know pretty quickly if someone does not listen to ICMPv6 Packet Too Big -messages. Not the first time I contact people about it but so far the only one I have not been able to convince is exactly someone really smart on some campus somewhere. I wrote many emails and tried to explain that IPv6 allows MTU's as low as 1280 bytes and that ICMPv6 is a must allow protocol but nope.

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