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The world in which IPv6 was a good design (2017)

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Re: The world in which IPv6 was a good design (2017)

#171

Post by JohnFen »

jeroenhd wrote: post #76
schoen wrote: post #71

Earlier quoted context omitted.

I gave a couple of talks promoting IPv6 in 1999 and I'm happy that I finally have it at home as a residential customer. (I didn't until this year.) I'm also working on a project to reclaim some IPv4 address space, which people often object to on the grounds that people should "just use IPv6". So I have to defend the legitimacy of the demand for IPv4 address space. In connection with this issue, I recently ran some DN…

> The over 99.9% of sites that still have an A record have it for a very good reason A records work on v4 and v6, so they'll probably stick around for a while. Perhaps they'll end up being concentrated around 4-to-6 forwarding NAT-as-a-service companies, but they're the fallback mechanism. I don't think anyone is advocating for dropping A all together unless you're really trying to pinch pennies. > I'd love to see so…

> Unlearning NAT

NAT is certainly not a firewall, but it is a very useful router function. I still don't understand how IPv6 makes NAT a thing that isn't useful to know.

I want to expose my servers to the internet through a single shared IP address, and to be able to have those servers exist on different IP addresses inside my network. How does IPv6 allow this without NAT?

Re: The world in which IPv6 was a good design (2017)

#172

Post by jandrese »

vbezhenar wrote: post #73
josephg wrote: post #69

Earlier quoted context omitted.

IPv4 addresses are getting increasingly expensive. And being behind an ISP’s NAT is terrible. I don’t want to share an IP with my street. It should be easy to run little network servers at home without worrying about reverse proxies or upnp or whatever nonsense we need today to make the network work. There’s plenty of numbers out there. Ipv6 lets my house have a whole subnet of them. It’s good.

I don't believe that they're expensive when I can rent VPS for few dollars per month. They might be more expensive than 10 years ago, but this cost is shared among all people behind NAT, so in the end it must be a rounding error. Running servers at home is a good thing to have, but I doubt that ISP cares much about users running servers at home. Users watch youtube and netflix. That's what they optimize for.

The days of getting a free IPv4 address when you rent a VPS are numbered. AWS is already rolling out a plan to charge by the hours for an IPv4 address and other VPN providers are paying attention.

Re: The world in which IPv6 was a good design (2017)

#173

Post by cyberax »

growse wrote: post #134
cyberax wrote: post #51

Earlier quoted context omitted.

8 bits for the home network feels cramped even now, my home network is at 56 devices. But 16 bits are fine for end-user networks. And once you go over 16 bits, you really need to start dealing with routing. > In the IPv4 world they can even have 24 bits (10.0.0.0/8) why should IPv6 have only 16 bits? It's definitely not enough. This is not a fair comparison. You won't have a 10.0.0.0/8 network in IPv4 that has 16 mil…

> And once you go over 16 bits, you really need to start dealing with routing. Disagree. you don't want to be routing unless you actually have to. A large flat network is more desirable a lot of the time (e.g thousands of devices in a DC) than a bunch of artificially carved up subnets. The reason you don't see them very often is because people have had to use IPv4, which means ARP, which just doesn't scale. At some p…

> Disagree. you don't want to be routing unless you actually have to. A large flat network is more desirable a lot of the time (e.g thousands of devices in a DC) than a bunch of artificially carved up subnets.

First, a /16 network is 65536 devices, which is pretty big as-is. And like in V4, you'll be able to disregard recommendations and choose a larger local net size (just change the netmask).

But it's a bad idea. You will have a shared media that can be brought down by erroneous broadcasts or devices. This is a classic story: https://www.computerworld.com/article/2581420/all-systems-do...

> ND fixes this, and allows for ridiculously large networks (the way our good maker intended).

ND doesn't solve it. It works in practice using the same old broadcast, just like ARP. Some switches might do ND snooping, but if you have thousands of devices, they'll overflow their internal tables and fall back to regular broadcasts.

ND also has unsolvable issues, like the neighbors cache size problems. Since you have a freaking /64 for your local network, you can't easily store the mapping for ALL hosts, and you're susceptible to various cache exhaustion attacks (including negative entries).

Re: The world in which IPv6 was a good design (2017)

#174

Post by cyberax »

throwaway154 wrote: post #146
cyberax wrote: post #51

Earlier quoted context omitted.

8 bits for the home network feels cramped even now, my home network is at 56 devices. But 16 bits are fine for end-user networks. And once you go over 16 bits, you really need to start dealing with routing. > In the IPv4 world they can even have 24 bits (10.0.0.0/8) why should IPv6 have only 16 bits? It's definitely not enough. This is not a fair comparison. You won't have a 10.0.0.0/8 network in IPv4 that has 16 mil…

16 bits is fine if thinking about discrete devices in the home. But what about thinking about the next step, neurons in the home. 65k's on the low side for home neuron count.

Are you sure you want to expose individual neurons to the Internet?

Re: The world in which IPv6 was a good design (2017)

#175

Post by uuddlrlrbaba »

fulafel wrote: post #65
mike_d wrote: post #20

IPv6 failed because they tried to boil the ocean. It was design by committee, where everyone got their pet feature thrown in to appease and gain consensus. Alternatively IPv4 is a mountain of small hacks, which is its biggest strength. We could have done a lot of good by adopting proposals to extend v4 like 0/8 and class D, but instead the decision was made to collectively drown the babies in the bathwater and insist…

It's looking more like a slow victory than a failure: https://www.google.com/intl/en/ipv6/statistics.html People like to complain a lot about the new features in v6, but they don't make it any worse as a v4 replacement.

Wow a ~40% migration over the course of 20 years. What a victory :|

Re: The world in which IPv6 was a good design (2017)

#176

Post by arka2147483647 »

jandrese wrote: post #167
arka2147483647 wrote: post #164

Earlier quoted context omitted.

> Point A: IPv6 is broken because it didn't go far enough Alternatively, it failed because it went too far. When you have an established system which is used everywhere, it is immensely difficult to replace it. Something like IPv4, with 64 bit addressed might have been easier to push through. Eg, addresses like 123.123.123.123.123.123.123.123. We have jumbo frames, why not jumbo addresses?

Because it comes with all of the drawbacks of IPv6 but also ditches some of the advantages. You still need to update every router and application. Network admins still need to learn something new. The two protocols still don't interoperate. If you're going to go through all of that trouble why only do a half measure. IPv6 is supposed to be the final version of IP.

> The two protocols still don't interoperate.

On the contrary, they would, the behavior's and quicks would be the same. And if we define, say, that if the last four components are zero, then the addr is the same as normal IPv4 address, then you could deploy the whole thing without having anybody assigning new addresses. NAT's/configs/etc could keep working.

The big problem with IPv6 is that everything has to be double-configured to support both IPv4 and IPv6. Two addressed for all. Different semantics. No backwards compatibility.

If you imagine that all network HW is recycled, say every decade, you could roll the thing in without having anybody to reconfigure everything. Eventually coverage would be complete. This cant happen with IPv6, because the double configuration problem. Extending vs replacement.

This is of course a pointless though experiment, because IPv6 is the route that was chosen.

Re: The world in which IPv6 was a good design (2017)

#177

Post by jandrese »

convolvatron wrote: post #127
ianburrell wrote: post #22

Earlier quoted context omitted.

Freeing up more IPv4 space wouldn't have helped. IANA was assigning /8 per month at the end. The extra space would have gone in less than a year. IPv6 would have worked better if they had made minimal changes to the support protocols. But it was have had slow adoption because there was no incentive to switch until addresses ran out.

I sat in on the ipv6 ietf meetings. That was certainly the intent (minimal changes). I still remain confused about why people think this is such a big deal. - changed arp. Ok, new design is better but that didn’t need to happen. Shouldn’t be a problem for anyone? - prefixes are an addition but there are really good arguments for them and not much downside. This can be argued I think - fusing the end system identifier…

Neighbor Discovery is basically ARP wearing a trenchcoat. The only people "hurt" by the change are the ones who were parsing the output of the arp command for whatever reason.

IMHO the biggest problem is that IPv6 address autoconfiguration was half-baked. There is no mechanism to inform anybody about which address you have configured for yourself, unlike IPv4's DHCP where a central server knows everyone's address and can do things like update DNS entries and configure security devices. Autoconfiguration also didn't include critical details like "Who provides DNS for the local network?" and "What's the NTP server?". There isn't even any way to authenticate that the Router Advertisement your machine receives is valid, although this problem is shared with DHCP. The committee seems to have put a lot of faith in anycast routing, which has never been a good idea outside of toy networks.

Re: The world in which IPv6 was a good design (2017)

#178

Post by MichaelZuo »

otabdeveloper4 wrote: post #152
systems_glitch wrote: post #147

Earlier quoted context omitted.

I really really don't get ISPs' difficulties in deploying IPv6. The only conclusion I can reach that actually makes sense is that they don't have the in-house talent to deploy it and refuse to hire someone who does. I guess there's just not enough pain in staying IPv4-only or halfway implementing IPv6 to make them get up and do something about it?

IPv6 doesn't actually solve any problem people wanted to solve. IPv4 (as used in practice) has 48 bits of addressing, we don't need more. What we do need is a standard way to do address translation for routing decisions, to replace the 1001 half-baked solutions for VPN and overlay networks that are used today. (Linux has something like five or six "standard" ways to tunnel IP over IP. WTF?)

> IPv4 (as used in practice) has 48 bits of addressing, we don't need more.

Do you mean an entire address space of NATs?

Re: The world in which IPv6 was a good design (2017)

#179

Post by jandrese »

cyberax wrote: post #14

Ugh. This is one of my favorite "what ifs" in the computer engineering. Things I would change: 1. Use 72-bit addresses. 56 bits for the network address, 16 bits for the end-user networks. 2. Just use the IPv4 "local subnet" prefix logic for broadcast domains. No "on-link" nonsense. 3. Replacing ARP with neighbor discovery via multicast messages to interface addresses is... ok? But it's not necessary. 4. Remove SLAAC…

IPv6 was built for a world with 64 bit machines. That's why the address is basically two 64 bit chunks, the first being the global network and the second being the local network. This is why you never allocate an IPv6 network smaller than a /64, so router manufacturers can optimize their hardware to only have to examine the half of the packet that the current routing step cares about.

Re: The world in which IPv6 was a good design (2017)

#180

Post by systemBuilder »

mike_d wrote: post #78
fulafel wrote: post #65

Earlier quoted context omitted.

It's looking more like a slow victory than a failure: https://www.google.com/intl/en/ipv6/statistics.html People like to complain a lot about the new features in v6, but they don't make it any worse as a v4 replacement.

IPv6 adoption is just the traffic shift from desktop to mobile. IPv6 kinda makes sense in mobile because it solves a problem of needing multiple addresses per person (phone, tablet, gaming device, etc) and the whole stack is maintained by two entities (the phone OS manufacturer and the carrier). It probably would have worked even better if it was far less complex and only solved the problem that was needed. https://w…

IPv6 only solves a problem if you don't understand the problem itself! Just because people have five devices doesn't mean they need 65,000 * 5 internet addresses ... there is an endpoint for every port and each device needs only a handful of ports if not only one! Each user can certainly get by with five ports on five shared ipv4 addresses.

As I said before IPv6 will never happen fully because it solves a non-problem very expensively - by assuming the whole world is 64-bit workstations!

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