And Now for Something Completely Different (was Re: IPv6 news)
Mark Smith
random at 72616e646f6d20323030342d30342d31360a.nosense.org
Sun Oct 16 08:02:47 UTC 2005
Hi David,
<snip>
>
> Well, if you NAT the destination identifier into a routing locator
> when a packet traverses the source edge/core boundary and NAT the
> locator back into the original destination identifier when you get to
> the core/destination edge boundary, it might be relevant. The
> advantages I see of such an approach would be:
>
> - no need to modify existing IPv6 stacks in any way
> - identifiers do not need to be assigned according to network
> topology (they could, in fact, be allocated according to national
> political boundaries, geographic boundaries, or randomly for that
> matter). They wouldn't even necessarily have to be IPv6 addresses
> just so long as they could be mapped and unmapped into the
> appropriate locators (e.g., they could even be, oh say, IPv4 addresses).
> - locators could change arbitrarily without affecting end-to-end
> sessions in any way
> - the core/destination edge NAT could have arbitrarily many locators
> associated with it
> - the source edge/core NAT could determine which of the locators
> associated with a destination it wanted to use
>
> Of course, the locator/identifier mapping is where things might get a
> bit complicated. What would be needed would be a globally
> distributed lookup technology that could take in an identifier and
> return one or more locators. It would have to be very fast since the
> mapping would be occurring for every packet, implying a need for
> caching and some mechanism to insure cache coherency, perhaps
> something as simple as a cache entry time to live if you make the
> assumption that the mappings either don't change very frequently and/
> or stale mappings could be dealt with. You'd also probably want some
> way to verify that the mappings weren't mucked with by miscreants.
> This sounds strangely familiar...
>
Certainly does. Apparently this or a similar idea was suggested back in
1997, and is the root origin of the 64 bits for host address space,
according to Christian Huitema, in his IPv6 book -
http://www.huitema.net/ipv6.asp.
A google search found the draft :
"GSE - An Alternate Addressing Architecture for IPv6"
M. O'Dell, INTERNET DRAFT, 1997
http://www.caida.org/outreach/bib/networking/entries/odell97GSE.xml
>
> Can two evils make a good? :-)
>
Not sure, however, two wrongs don't make a right, but three lefts do.
Regards,
Mark.
--
The Internet's nature is peer to peer.
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