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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)

#161

Post by colmmacc »

cyberax wrote: post #24
ggm wrote: post #5

35% worldwide by population of users in random samples at APNIC: https://stats.labs.apnic.net/ipv6/XA US on 50%, India on 70% and China just shy of 40% -As China continues to grow (and it will) the likely outcome is > 50% IPv6 Capable. I doubt any new Mobile deployment will be single stack, the most likely is pure IPv6 with CGN for 4. So Africa which is still in growth, the most likely outcome is dualstack preferring…

There will be no larger MTU, this battle is lost. 1500 will live forever. If it makes you feel better, think about it as if Ethernet packets are just oversized ATM cells. Solving PMTU problem would have required reifying the MTU to the IP layer. It could have been done like this: 1. Use a 16-bit field in the non-checksummed portion of the IP header. Initially this field is set to the MTU of the link that originates t…

The approach obviously doesn't work at all for unidirectional protocols. This approach also doesn't work when there are multiple equal cost paths, but with different MTUs. Which used to be more common and now tends to only happen when changing link technologies. The original sender needs not just the discovered MTU, but the original header information that may have been used for flow hashing.

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

#162

Post by magicalhippo »

fulafel wrote: post #31
unethical_ban wrote: post #28

I've only dabbled in IPv6, but the one thing that blew my mind was that you cannot set DNS automatically without DHCPv6. Other methods of "automatic addressing" are thus useless.

This would be relevant in v6-only networks, but in practice everyone also runs v4 which and v4 dhcp which gets you dns. (Also there's a DNS option in router advertisements now like subling comment said)

Android ignores any IPv4 DNS address it gets if it gets an IPv6 address. Instead it falls back to Google's own DNS servers. So if you got Android devices in your house, you need to configure a IPv6 DNS server. AFAIK a IPv4 DHCP server can't hand out a IPv6 DNS address.

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

#163

Post by cyberax »

toast0 wrote: post #81
cyberax wrote: post #24

Earlier quoted context omitted.

There will be no larger MTU, this battle is lost. 1500 will live forever. If it makes you feel better, think about it as if Ethernet packets are just oversized ATM cells. Solving PMTU problem would have required reifying the MTU to the IP layer. It could have been done like this: 1. Use a 16-bit field in the non-checksummed portion of the IP header. Initially this field is set to the MTU of the link that originates t…

If you don't do 2, you can have 3) if the packet is too big, just truncate it. If the destination gets a packet that isn't as big as it says in the header, it was truncated, and the MTU is the size of the packet it received. Even easier! You still really should occasionally probe up, in case the path changed, but that's not very well done today either.

Yeah. You still need a way to reflect the discovered MTU value to the sender somehow, but this can be taken care of by higher-level protocols.

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

#164

Post by arka2147483647 »

lproven wrote: post #96

I have several times cited it as a key article, more insightful than almost anything else I've ever read about IPv6, but I concede it is overlong and unclear and needs more illustrations. (Which, as a technical writer myself, I generally regard as a crutch.) I think the core argument can be summarised as this: 1. IPv6 is flawed because it has 2 main layers, but it needed 3. 2. It understands physical addresses, and i…

> 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?

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

#165

Post by JohnFen »

jeroenhd wrote: post #66

IPv6's biggest problem remains not that it's badly designed (at least not nowadays, there were problems but they were solved ten years ago) but that millions of network engineers never bothered to look deeper into IPv6 than "I don't get it, this feels off". You can't make a backwards compatible "IPv4 with more bits" like people dream of. L2 routers and middleboxes would still need to be replaced, software would still…

> The world now runs on HTTPS on top of UDP or TCP on top of IPv6/4, on top of some kind of wire that carries ethernet.

Am I misunderstanding what you mean by "the world" here? Most of the networks I work with are not HTTPS on top of UDP or TCP.

> Grumpy people, clinging to what they know, delaying unavoidable change until the very last moment

This seems unrealistically broad. For all of the things you cite, there are downsides along with upsides. For all of them, we lose something as well as gain something. That means there's a cost (even ignoring the cost of making the change itself) as well as a benefit. That means a cost/benefit calculation takes place, and the results of that calculation are not guaranteed to be in favor of the replacement tech.

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

#166

Post by [deleted] »

backendanon wrote: post #138
jeroenhd wrote: post #66

IPv6's biggest problem remains not that it's badly designed (at least not nowadays, there were problems but they were solved ten years ago) but that millions of network engineers never bothered to look deeper into IPv6 than "I don't get it, this feels off". You can't make a backwards compatible "IPv4 with more bits" like people dream of. L2 routers and middleboxes would still need to be replaced, software would still…

> People cared about the IPv6 privacy risks but never let go of that concept even after rfc4941 fixed that oversight. In my own experience in our household, IPv6 destroys privacy.

[deleted]

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

#167

Post by jandrese »

arka2147483647 wrote: post #164
lproven wrote: post #96

I have several times cited it as a key article, more insightful than almost anything else I've ever read about IPv6, but I concede it is overlong and unclear and needs more illustrations. (Which, as a technical writer myself, I generally regard as a crutch.) I think the core argument can be summarised as this: 1. IPv6 is flawed because it has 2 main layers, but it needed 3. 2. It understands physical addresses, and i…

> 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.

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

#168

Post by systemBuilder »

I was asked by my employer in 2003 when IPv6 would replace IPv4? After substantial research, my answer was, "never"!!! I almost got fired for that answer but I am correct so far.

There are a large class of people out there who do not understand the end to end argument in system design and who never saw a piece of bloatware they didn't love. For them IPv6 will happen tomorrow. They are to internet like maga people are to democracy - caustic.

In 2004 IPv6 was hyped as solving the impending IPv4 address shortage. NAT had already been invented and there was no shortage as IPv4 addresses were allocated as inefficiently as possible and there was no market to buy and sell IP addresses nor was there any rental cost for owning ipv4 addresses. So it was solving a non problem.

My employer Qualcomm eventually proposed using IPv6 for cell phone handsets in an overlay network called openran. This was a convenience and not a necessity because there are more than 4 billion cell phones in the world.

You just don't need these bloated addresses in IPv6. You need banks of addresses mainly for the server. The client never needs 65,000 incoming or outgoing connections. The number of client computers in the world that are running as servers and that need open datagram accessibility from anywhere in the internet is virtually zero. Want it? yes! Need it - meaning impossible to do without it - No! There are always bridging workarounds to avoid giving client machines dedicated IP addresses!

IPv6 is not respectful of small system design and hardly provides usable improvements to IPv4. IPv6 was a marketing tool invented by Cisco to sell bigger more expensive routers, not to solve a problem with any economy ... It is especially detrimental to IOT.

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

#169

Post by derefr »

tenebrisalietum wrote: post #121
lproven wrote: post #96

I have several times cited it as a key article, more insightful than almost anything else I've ever read about IPv6, but I concede it is overlong and unclear and needs more illustrations. (Which, as a technical writer myself, I generally regard as a crutch.) I think the core argument can be summarised as this: 1. IPv6 is flawed because it has 2 main layers, but it needed 3. 2. It understands physical addresses, and i…

I read the article, also found it a bit confusing and wayward, and couldn't quite articulate why I disagreed with it at first, but I think I can now. - The "mobile IP" problem isn't IP's job and should not be. IP should be as stateless as possible because this makes it cheap and easy to add capacity and redundancy to a network. - IP addresses are assigned to interfaces, not people, computers, devices, applications, n…

> The "mobile IP" problem isn't IP's job and should not be. IP should be as stateless as possible because this makes it cheap and easy to add capacity and redundancy to a network.

But, to be clear, many implementations of IP (both IPv4 and IPv6) do already have "mobile IPs." There's nothing stopping you from having "mobile IPs." They're just complex, and only work when everywhere the IP can move between all exists within a single AS.

• You can move between multiple wireless APs in a conference hall, and have a layer-3 address that follows you as you switch network segments and thus acquire new layer-2 addresses (which means that the packets destined to that address are being dynamically re-routed at some upstream switch, as the address assignment changes.)

• You can move between cellular antenna and frontend infra (think: WiMax or 5G APs) at different places in a city, while remaining connected to a single cellular backend infra (what you'd think of as a "cell tower") and thus holding a single persistent L3 address.

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

#170

Post by jandrese »

kalleboo wrote: post #102
mkl wrote: post #93

Earlier quoted context omitted.

It spikes up 3-5 percentage points every weekend. Presumably mobile use goes up and computer use goes down.

Corporate use goes down and Residential use goes up. Corporate networks were the last to drop XP, the last to drop IE, and will be the last to adopt IPv6.

That's not quite true. Even after corporate users have switched the government will still be on V4. The US military is drowning in IPv4 addresses and feels little pressure to switch.
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