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DJB was wrong... even if he was right too.DJB was wrong... even if he was right too.Posted Jan 27, 2011 10:10 UTC (Thu) by dan_a (subscriber, #5325)In reply to: DJB was wrong... even if he was right too. by bojan Parent article: LCA: IP address exhaustion and the end of the open net
One of the reasons why IPv6 is being introduced, separate to the address space exhaustion issue, is because of an explosion in the size of routing tables.
By aggregating together large numbers of fragmented IPv4 routes which belong to the same autonomous system the routing table shrinks massively which theoretically reduces router memory requirements and routing table lookup times.
If we kept the old, fragmented, IPv4 routes in the new IPv6 table then this benefit would never ever be felt. That's why the global migration plan does not include embedding existing IPv4 addresses in IPv6.
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The routing table issue Posted Jan 27, 2011 14:48 UTC (Thu) by mstefani (subscriber, #31644) [Link]
And how does IPv6 alleviate the routing table explosion?
By assuming an hierarchical internet where everybody but the tier 1 providers are single homed? And to enforce their "reality" they didn't give out provider independent IPv6 addresses? That helped tremendously with acceptance of IPv6 in the enterprise space </irony>. Grudgingly they had to change that policy a couple of years ago. That brought the routing table explosion problem back. And it would make matters even worse due to the increased size of the IP address. The fix? Ignore the problem for now as IPv6 is barely used...
IPv4 addresses run out this year? We run into the routing table issue 8 years ago. Trying to route something smaller than a /24 is an exercise in futility. But we had even fun like "Your IP address is from an IP space that is allocated in /20 blocks; we are filtering out any routes smaller than that. Have a nice day."
The routing table issue Posted Jan 27, 2011 15:41 UTC (Thu) by foom (subscriber, #14868) [Link]
> By assuming an hierarchical internet where everybody but the tier 1 providers are single homed?
Actually the (completely unworkable) idea was that people who had multiple providers would simply have multiple IP addresses, and advertise all of them. That *possibly* could have even worked (with a lot of effort) if TCP supported multiple endpoints and transparently switched between them in real-time. But, it doesn't.
The one (pretty minor) remaining thing IPv6 does to help reduce routing-table size is reduce fragmentation of the address space -- a single organization at a single location is less likely to need multiple non-contiguous addresses spaces than in IPv4.
The routing table issue Posted Jan 28, 2011 7:20 UTC (Fri) by butlerm (subscriber, #13312) [Link] That *possibly* could have even worked (with a lot of effort) if TCP supported multiple endpoints and transparently switched between them in real-time. But, it doesn't.That is why they invented SCTP, which does all that and more. Perhaps too much even.
DJB was wrong... even if he was right too. Posted Jan 28, 2011 7:18 UTC (Fri) by cmccabe (guest, #60281) [Link]
Moore's law is still holding. Twice as many transistors will be able to fit on a single chip 18 months from now.
On the other hand, the world population growth rate is well under 1% per year (according to wikipedia.)
Sound like the routing table problem will solve itself pretty quickly, without us doing a thing.
Nope. Posted Jan 28, 2011 12:20 UTC (Fri) by khim (subscriber, #9252) [Link] Routing table is supposed to handle devices, not people. Population is not growing, yet number of devices is growing exponentially. You have computers, mobile phones, power meters and other gadgets connected to the internet. Often they use totally different networks. Heck: there are more mobile phones users then there are IPv4 addresses! So no, Moore's law will not save us.
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