Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How engineers at Digital Equipment Corp. saved Ethernet

spectrum.ieee.org

Post reply on HN
Print view View original

41–50 of 109 posts

Re: How engineers at Digital Equipment Corp. saved Ethernet

#41

Post by mixmastamyk »

Dylan16807 wrote: post #33
mixmastamyk wrote: post #15

Earlier quoted context omitted.

Similar to how it has been done with phone numbers. I saw this done in Brazil for example. You add a digit to the front and put all existing address on 0.*. Short number dials are assumed to be 0.*. Update OS and hardware. Then you allocate across the new digit much later as time goes on. The thing with phone infrastructure though is that it is centralized. So may happen in a reasonably coordinated rollout. Global in…

If you had to deal with a hundred million different kinds of dialing software, that method wouldn't work out so well. > If we could get a five byte address written in hex it would be somewhat user friendly. For local addresses, you can use fec0::zzzz. Do you need to memorize or hand-type global addresses very often?

> that method wouldn't work out so well

How well did IPv6 turn out by that criteria?

> memorize or hand-type

We read things many more times than we type them. Yes, gibberish at 4x the length is substantially harder to deal with. I do write addresses occasionally and with IP4 it is at least possible, if not desirable.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#42

Post by simoncion »

firecall wrote: post #18
spintin wrote: post #3

[flagged]

Has IPv6 been a failure? All I know is that IPv4 is still around. And without knowing the IP Addresses of devices on my LAN, by home network would be harder to manage!

> All I know is that IPv4 is still around.

So what? IPv6 coexists with IPv4 just fine. As has been made abundantly clear over the years, there's no need to have a flag day for a big cutover in order to adopt IPv6.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#43

Post by ianburrell »

Dylan16807 wrote: post #38
ndriscoll wrote: post #30

Earlier quoted context omitted.

You can know the IP addresses on your LAN. If you'd like you can assign multiple addresses per interface, so that you have global and local addresses. e.g. local addresses fc00::1 for your router, fc00::2 for your desktop, fc00::3 for your phone, etc. If you want, you can use your global prefix with ::1 ::2 and ::3 for your global addresses too. You don't have to use privacy extensions if you don't want to. Things li…

Addresses starting with fc are reserved. I would suggest using either fec0 or fd00. Which is still not best practices, but it's a lot closer. (fec0 is deprecated, and fd is supposed to be followed by a randomly chosen 40 bit site ID but you can lie and say your random number was 0)

fc00::7 is the ULA range. It is not reserved. It is the right range to use for an internal network. There is no reason to prefer fc00 over fd00.

fec0 is the site-local addresses. Nobody should be assigning addresses in that range since they are made automatically. Using site-local addresses makes sense for single subnet network like most home networks.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#44

Post by gumby »

non-chalad wrote: post #24
gumby wrote: post #2

What a great story. The spanning tree algo is under appreciated: this allowed people who didn’t understand networking to plug networks together the way you would plug extension power cables together,* making networking simple ( or alternatively insanely broken, when people had 400 computers on a single LAN with a rat’s nest of bridges and hubs…but unlike the extension cord case, nothing would catch literal fire). * d…

Too late: Tried this at work; Did a marvelous job sharing satellite internet with the whole barracks.

Sounds like things worked out, even if all you shared was your porn.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#45

Post by ianburrell »

ndriscoll wrote: post #30
firecall wrote: post #18

Earlier quoted context omitted.

Has IPv6 been a failure? All I know is that IPv4 is still around. And without knowing the IP Addresses of devices on my LAN, by home network would be harder to manage!

You can know the IP addresses on your LAN. If you'd like you can assign multiple addresses per interface, so that you have global and local addresses. e.g. local addresses fc00::1 for your router, fc00::2 for your desktop, fc00::3 for your phone, etc. If you want, you can use your global prefix with ::1 ::2 and ::3 for your global addresses too. You don't have to use privacy extensions if you don't want to. Things li…

I use mDNS for hosts on home network. They have IPv6 addresses, multiple ones, but I don't care what they are because I have never used them.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#46

Post by aleph_minus_one »

themerone wrote: post #8
eej71 wrote: post #6

Earlier quoted context omitted.

I think the great architectural challenge would be - how does one add that byte to the IP header in a non-breaking way?

There's a surprising number of people who think you could magically expand the IPv4 address space in a backwards compatible manner.

> There's a surprising number of people who think you could magically expand the IPv4 address space in a backwards compatible manner.

There is a (somewhat) backward-compatible way to do this at least for TCP and UDP:

Instead of assigning an IPv4 network prefix (or one single IP address as a special case), assign a tuple (IPv4 network prefix, port prefix), i.e. by firewall rules not every source port can be used from every IP address for TCP and UDP connections.

Is this a better solution than IPv6? I clearly don't think so. But it is an ugly, hacky solution that is theoretically possible if one really insists that one wants to keep using IPv4 (only), and needs to magically expand the address space.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#47

Post by Dylan16807 »

ianburrell wrote: post #43
Dylan16807 wrote: post #38

Earlier quoted context omitted.

Addresses starting with fc are reserved. I would suggest using either fec0 or fd00. Which is still not best practices, but it's a lot closer. (fec0 is deprecated, and fd is supposed to be followed by a randomly chosen 40 bit site ID but you can lie and say your random number was 0)

fc00::7 is the ULA range. It is not reserved. It is the right range to use for an internal network. There is no reason to prefer fc00 over fd00. fec0 is the site-local addresses. Nobody should be assigning addresses in that range since they are made automatically. Using site-local addresses makes sense for single subnet network like most home networks.

> fc00::7 is the ULA range. It is not reserved. It is the right range to use for an internal network. There is no reason to prefer fc00 over fd00.

fc00::/7 is the ULA range.

It is made out of two halves. fc00::/8 and fd00::/8

fc00::/8 is reserved. People are only allowed to use fd00::/8

> fec0 is the site-local addresses. Nobody should be assigning addresses in that range since they are made automatically. Using site-local addresses makes sense for single subnet network like most home networks.

None of my adapters have automatic fec0 addresses, they only have global and fe80. So can you elaborate on that?

Re: How engineers at Digital Equipment Corp. saved Ethernet

#48

Post by inopinatus »

gumby wrote: post #2

What a great story. The spanning tree algo is under appreciated: this allowed people who didn’t understand networking to plug networks together the way you would plug extension power cables together,* making networking simple ( or alternatively insanely broken, when people had 400 computers on a single LAN with a rat’s nest of bridges and hubs…but unlike the extension cord case, nothing would catch literal fire). * d…

> people who didn’t understand networking

A couple of decades ago I witnessed a classic demonstration of Weinberg's Corollary¹ when a spanning tree misconfiguration on a freshly-installed BlackDiamond disabled LINX for hours, throwing half of Britain's ISP peering into chaos. The switch in question was evidently cursed: it'd been dropped on my foot earlier that week, thus disabling me for hours, and everyone else involved in that project was dead within two years.

__

[1] "an expert is a person who avoids the small errors while sweeping on to the grand fallacy"

Re: How engineers at Digital Equipment Corp. saved Ethernet

#49

Post by Aloha »

gumby wrote: post #2

What a great story. The spanning tree algo is under appreciated: this allowed people who didn’t understand networking to plug networks together the way you would plug extension power cables together,* making networking simple ( or alternatively insanely broken, when people had 400 computers on a single LAN with a rat’s nest of bridges and hubs…but unlike the extension cord case, nothing would catch literal fire). * d…

STP is basically magic - and being able to reliably optimize it to reduce reconvergence time makes you a magician.

Re: How engineers at Digital Equipment Corp. saved Ethernet

#50

Post by Dylan16807 »

mixmastamyk wrote: post #41
Dylan16807 wrote: post #33

Earlier quoted context omitted.

If you had to deal with a hundred million different kinds of dialing software, that method wouldn't work out so well. > If we could get a five byte address written in hex it would be somewhat user friendly. For local addresses, you can use fec0::zzzz. Do you need to memorize or hand-type global addresses very often?

> that method wouldn't work out so well How well did IPv6 turn out by that criteria? > memorize or hand-type We read things many more times than we type them. Yes, gibberish at 4x the length is substantially harder to deal with. I do write addresses occasionally and with IP4 it is at least possible, if not desirable.

> How well did IPv6 turn out by that criteria?

About the same. So it's good we made it big for the future.

> Yes, gibberish at 4x the length is substantially harder to deal with.

I find copying and pasting to be pretty easy, and if you're looking at your own machines you can organize them all with the last 4 characters.

I don't have to compare random internet servers very often.

Post reply on HN