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The Internet

O'Reilly's IPv6 Overview 40

Posted by timothy from the more-than-sticks-can-be-shaken-at dept.
Scooter[AMMO] writes: "I thought people might be interested in this IPv6 overview currently on O'Reillynet. It touches on what a lot of us already know, like a larger addressable space, security, and mobility, but it also goes into some detail that others may not know yet. It gives information on how addresses are divided between host bits and network bits, address creation, NDP, name resolution, multicasting, localnets, and localsites. It also has RFC references for the more demanding researchers among us."
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O'Reilly's IPv6 Overview More

O'Reilly's IPv6 Overview

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  • Hmmm, since you mention patents, I'll just say:
    DNS [is.co.za]. Can you say prior art?
  • whois.arin.net and do lookups for those huge class A blocks. Bbnplanet at least uses their 4.x block while GE and few other large companies just have them reserved.

  • Aparently with Cisco's next major IOS train release, there will be support for IPV6 which I'm certainly looking forward to.
  • Three letters:
    D N S
    Take a look at anything in the domain ipv6.drobnak.com for examples. I have a mini IPv6 net setup here, using a very nice tunnel broker - hurrican electric. (www.he.net [he.net])
    You use a 'quad A', AAAA, or an A6 record to put IPv6 addresses into the DNS database. Quite simple, just as long as you have a dns provider who supports it. (ie www.worldwidedns.net [worldwidedns.net])

    -Matt
  • Well, okay, sure...but he's talking about the simple case. And if you qualify his point a little, he's right. Portforwarding only enables a single box to act as the server; fine for a home network but not for a corporate LAN. Proxying requires additional code running somewhere to compensate for the problems introduced by the NAT.

    I'm writing an application proxy right now, and guess what---embedding routing info in application packets adds additional routing logic that is separate from your normal routing infrastructure. Can you say security hole?

    He is pointing out how NAT is an incomplete solution to the problem of mapping multiple hosts to a single v4 address. And he's right, it's a pain in the ass.

  • Sorry, I didn't realise Microsoft filed for bankrupcy and *BSD took control of the desktop.

    Tongue in cheek aside, I'd venture to guess a huge percentage of the net's traffic flows through *BSD hardware.

    Microsoft owns the desktop, UNIX owns the net's infrastructure.

    Japan has a huge IPv6 infrastructure ready to roll, this doesn't mean the end users would have to adopt it right away. IPv6-to-IPv4 products exist already.

    grub

  • EUI-64 (Score:1)

    by jochen ( 2803 )
    Very impressive article.
    However, unfortunately, the author got the EUI-64 algorithm wrong. Before inserting the fffe in the middle of the MAC address, the universal/local bit has to be inverted. So 01:23:45:67:89:ab will give you as host part of the IPv6 address: 0323:45ff:fe67:89ab

    --jochen
  • So you're saying all Cisco and Microsoft (or even Linux) users can take a few minutes to install v6 on their current hardware/OS and have everything working just fine?

    Didn't think so.
  • Yeah. The article says [emphasis mine]:
    For example, with Ethernet, the 6-byte (48-bit) MAC address is usually filled with the hex bits "fffe" in the middle -- the MAC address

    01:23:45:67:89:ab

    results in the EUI64 address

    01:23:45:ff:fe:67:89:ab

    which again gives the host bits for the IPv6 address.

    ::0123:45ff:fe67:89ab

    Huh? Wouldn't it be much better to make this at the beginning, like:

    ::fffe:0123:4567:89ab

    Or better yet, use those the first two or three F's for subnet addresses. Let's get real here: 33 bits are enough to uniquely identify every single human in the world. So prepending a MAC supertype of a few bits should do just fine. What point is there in arbitrarily sticking it in the middle, and basically forcing everyone to waste these bits?

  • Well, when you have 340,282,366,920,938,463,463,374,607,431,768,211,45 6 possible addresses, do you want to be using a long string of numbers? The numbers aren't all meant to be memorizable, that is why there are things such as autoconfig and DNS.
  • It's more its 4hex digits a set not 256
  • Why do you say IPv6 is faster than CLNP?

    The usual excuse is that IPv6 has fixed-length address fields which are easy to handle, say, as struct's. But who says CLNP can't? While CLNP allows many AFIs, it's quite reasonable for the IETF to standardized on a narrow subset, with defined length.

    Little work has been done lately on speeding up CLNP, but I think it should be quite feasible to run it through the fast path.
  • IPv6 is a failure, and has been for the ten years or so that it's been in the works. Now that Cisco has lost most of its technical talent, it's finally pushing something that should have died years ago.

    IPv6 was misbegotten in the first place. There was a working protocol, CLNP, designed for the OSI programme. While OSI had many errors, CLNP, its equivalent of IP, was very good. It had a flexible address field. The first byte was the "authority and format identifier" (AFI), which indicated how to parse the rest. The maximum length was 20 octets but it varied depending on the AFI. Then came the "initial domain identifier" (IDI), which corresponded to network, and the "domain specific part" (DSP), which corresponded to a host on the network (and which could have a subnet-like hierarchy). CLNP was in Cisco, Wellfleet, and other routers over ten years ago! Applied to the Internet, it was called TUBA (TCP and UDP with Bigger Addresses).

    The IETF almost standardized on TUBA; had they done so, the migration would have been done years ago and we probably wouldn't have had NAT, except maybe for some firewalling. The opposition came about because it was tained by OSI, a religious issue among some immature IETF hotheads. Paul {Francis|Tsuchia} of Bellcore and Steve Deering each wrote their own candidate replacements for IPv4, called PIP and SIP (Paul's and Steve's IP, respectively). Both were undergraduate quality. They merged their efforts (the anti-OSI alliance) into what we now call IPv6. At the last minute, Vint Cerf (the Chauncy Gardner of the Internet) switched his vote from TUBA to IPv6. And real progress in the IP layer basically stopped.

    IPv6 doesn't do what it's supposed to. The article at least doesn't claim that its flows are useful for QoS; they're not. The address space is horribly wasteful; because the low-order 64 bits are globally unique (based on MAC), the net result is 64 effective bits, twice. Security is no better than with IPv4. The long addresses result in more header overhead, more bandwidth wasted, and thus either worse performance or more cost. Think of how the bigger headers will work with short-payload streaming payloads!

    They should put this turkey out of its misery. There are LOTS of IPv4 addresses in reserve. Properly allocated, 32 bits should last for a decade or more. Of course many Class As were given out wastefully back in the old days, but we really don't need globally unique addresses for every appliance in every house anyway.
  • This is very stupid. Right now there is a business in selling IP addresses due to scarcity, but once IPv6 is implemented, the market of selling IPs is over. Of course most providers actually "like" the current system; so they dont really care to implement IPv6 yet. While IPv6 address the issue of NATs even better than the old IPv4; it is actually supposed to be less used than it is today, or at least only used when desired; and not as an unfortunate need like it is right now with IPv4. Im really happy that Japan is so serious about implementing it; i hope more countries follow.

    OK, try reading this post after these:
    s/(IP addresses|IP address|IPs)/recorded music
    s/IPv6/Napster/g
    s/IPv4/FTP/g
    s/NATs/site indexing/g

    Interesting reading, eh?

  • Huh? Wouldn't it be much better to make this at the beginning, like:
    ::fffe:0123:4567:89ab
    Or better yet, use those the first two or three F's for subnet addresses.
    I did not invent this "fffe-in-the-middle" thing out of thin air. I took it from IEEE's EUI-64 spec, which says that this is the 64-bit identifier corresponding to a given 48-bit MAC address.
    Not every medium is ethernet, some have 64 bit node identifiers and you can't just truncate them without risk of duplicates. See RFC 2373, 2462, 2464 and references in the latter.
    Let's get real here: 33 bits are enough to uniquely identify every single human in the world.
    But you can't assign identifiers with perfect efficiency. See RFC 1715 for examples.
  • Jeez, I know when a statement is tongue in cheek..
    If you notice the original article, the submitter was saying RFCs are too hard to read.
    This was a neat opportunity to point out that RFCs should be mandatory reading, for techies, at least.
    (And also to prevent any bright kid out of law school from taking the idea seriously).

    And the +2 was because I have earned it, and on merit. I haven't karma whored yet.
  • CLNP is hard on the router's processors. Unless you want MPLS used all over the internet it's unfeasible to use CLNP on very fast networks. IPv6 was made to be fast. Most of it's pitfalls are a result of that effort. And I think it will be even more an advantage in the future to have a fast protocol than another very complete but slow.

  • So you're saying all Cisco and Microsoft (or even Linux) users can take a few minutes to install v6 on their current hardware/OS and have everything working just fine?

    If you run OpenBSD (and I believe FreeBSD), you'll see that you're already IPV6-ready

    (pardon the formatting for this paste)

    $ ifconfig rl0 rl0: flags=8843 mtu 1500 media: Ethernet autoselect (100baseTX) status: active inet 192.168.212.180 netmask 0xffffff00 broadcast 192.168.212.255 inet6 fe80::248:54ff:fe4b:aa9b%rl0 prefixlen 64 scopeid 0x1
    grub
  • Can you say dumbarse [dictionary.com]?
  • This is very stupid. Right now there is a business in selling IP addresses due to scarcity, but once IPv6 is implemented, the market of selling IPs is over. Of course most providers actually "like" the current system; so they dont really care to implement IPv6 yet. While IPv6 address the issue of NATs even better than the old IPv4; it is actually supposed to be less used than it is today, or at least only used when desired; and not as an unfortunate need like it is right now with IPv4. Im really happy that Japan is so serious about implementing it; i hope more countries follow.

    --

  • Sorry, I didn't realise Microsoft filed for bankrupcy and *BSD took control of the desktop.
  • Interesting that you pull one sentence out of context in order to give the impression the writer is talking about IPv6, when in fact they are actually talking about exactly what you propose. Just before the line you quote the writer said:
    Several approaches have been made to solve the problem. A very popular approach is to not assign a worldwide unique address to every user's machine, but rather to assign them "private" addresses...
    When the article says "It has problems..." the writer is talking about what you suggest, not about IPv4. The only "misleading" thing here it your attempt to spin the article.
  • Now while the space for network and subnets is sufficient, using 64 bits for addressing hosts seems like a waste. It's unlikely that you will want to have several billion hosts on a single subnet, so what is the idea behind this?

    Can you imagine the broadcast traffic you'd get on a several billion host subnet? I would hope you don't have an IPv6 aware rwhod running. :-)

  • What of IPv6 on the internet? (Score:2)

    by Anonymous Coward
    I hear much about IPv6. But where do I get my ARIN/RIPE/APNIC issued, ok-to-use-on-the-net IPv6 address? How does the routing work? I can't just do this myself without the blessing of my ISP. And what ISPs have IPv6 address blocks allocated to them? What do they charge for them? Why are they charging for them? I thought IPv6 addresses were supposed to be so plentiful that they'd be free? What about the root servers and DNS. Nothing I know of resolves to an IPv6 address. How do I "telnet" to an IPv6 address?

    There seems to be a fscking chasm of missing pieces in the IPv6 rollout. Set it up on your LAN, but I don't see it in the internet arena for at least the next 20 years.

  • Broadcasting is outmoded in IPv6 so that is not an issue. Only unicast and multicast operations are available. Mashton
  • I have an idea. I should probably patent this first but I'll pass it along since I love Open Source ideas. How about we create some kind of huge distributed database of "names" to would map to these IPv6 addresses? Then we could just remember these names instead. :-) Then the only time you'd need the IP address is when you're configuring thie naming database thingamajig and your machine.

  • IPv6, NAT, and the little people (Score:5)

    by ClayJar ( 126217 ) on Saturday May 26, 2001 @07:48AM (#196942) Homepage
    It seems that every overview of IPv6 I read talks about it eliminating the need for NAT. However, this is only going to be in the case of, for example, a large corporation that is using NAT solely to avoid spending money on IP addresses. In my little piece of the world, I run NAT (IP masq) NOT because there aren't enough addresses but rather because my ISP adds about $7/month for each additional computer, and only up to three on a home account (at least double the price if you want a business account).

    There is no way in H-E-double-hockey-sticks that my ISP is going to just up and say "Okay, now there are plenty of addresses, so we'll stop charging extra for additional computers." They're not going to just let me have six computers connected with IPv6, IPv4, or whatever. For the home user (cable modem, xDSL, modem, or whatever), there will always be a need for NAT.
  • Just run Window 9x, and let NetBIOS take care of it all!

    --
  • Here's a good cisco doco that I should have included in the origional post: here [cisco.com]
  • 111.222.333.444.555.666 That would give, to my math, 256^6, or 281 trillion, IP addresses. 281,474,976,710,656 to be exact.

  • Re:Why does IPv6 matter right now? (Score:4)

    by wrero ( 314883 ) on Saturday May 26, 2001 @08:23AM (#196946)

    www.cisco.com/ipv6 [cisco.com]

    http://msdn.microsoft.com/downloads/sdks/platform/ tpipv6.asp [microsoft.com]

    What's the problem?

  • NAT (Score:3)

    by SuiteSisterMary ( 123932 ) <slebrunNO@SPAMgmail.com> on Saturday May 26, 2001 @07:53AM (#196947) Journal
    It has problems, as the machines hidden behind the global address can't be addressed, and as a result of this, opening connections to them -- which are used in online gaming, peer-to-peer networking, etc. -- is not possible.
    Misleading, if not outright wrong. Portforwarding? Proxying?
  • Of course, I'm already running IPv6. I just wish the airlines would get their acts togeather and upgrade the switches in first class.

    Trolls throughout history:

  • I've been too lazy to look up how IPV6 works, but this article sums it up neatly.

    Now that I finally understand what all:those::colons:are in the addresses my OpenBSD box spits out, I'm no longer afraid of them. It's actually pretty straightforward.

  • There is no way in H-E-double-hockey-sticks that my ISP is going to just up and say "Okay, now there are plenty of addresses, so we'll stop charging extra for additional computers."

    Why? How can you be so sure? What if a small ISP decides to differentiate itself from the competition by saying "Now that IPv6 addresses are practically free, each of our customers gets a /64 at no extra charge."? Although flat-rate pricing might not make sense if you allow that many machines to be connected...

  • Why does IPv6 matter right now? (Score:3)

    by electricmonk ( 169355 ) on Saturday May 26, 2001 @08:07AM (#196951) Homepage
    We all know that no one will be deploying IPv6 until Cisco starts to support it in its router software. Furthermore, it won't be deployed on a near universal basis until Microsoft decides to get off their asses and support it. So don't count on having any of the benefits of IPv6 at your disposal any time soon...
  • Will firewalls become obsolete after IP4 is gone?
    • Broadcasts are no longer available in IPv6 in
    • the way they were in IPv4, this is where multicasting comes into play. Addresses in the ff::/8 network are reserved for multicast applications, and there are two special multicast addresses that supersede the broadcast addresses from IPv4. One is the "all routers" multicast address, the others is for "all hosts".

    It seems like the "all hosts" "multicast" thing is similar to what today's netbios and dhcp use. Is this incorrect?
    --

  • With provider assigned space in the network address, how does any organisation do multi-homing?
    Or do they change addresses each time a link goes down?
    Or will we have a similar situation as of today, where we lease provider space from APNIC/ARIN/RIPE?
    And for smaller organizations which do not have that large requirements?

  • Cisco has been developing IPv6 software for some time. Detatils are at www.cisco.com/ipv6, and anyone with a registered login can download the software and try it out for most major platforms.

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