On 21/10/10 16:07 +0100, Ben Butler wrote:
Hi,
Showing my ignorance here, but this is one of the things I have wondered, given that we run both v4 and v6 for a period of time on the Internet, presumably at one time or another a particular resource may only be able in v4 land, then v4 and v6, then finally v6 only.
I have never been particularly clear how an end network that exists only in v4 or v6 address space is able to access a resource that only exists in the other. Is can sort of see some freaking huge NAT box type thing that summarizes v6 in a v4 address scope or contains the v4 address range at some point inside the v6 address space - but how can a v4 host get to a hot in v6 world that sits outside this without going through some form of proxy / nat gateway between the two.
Or are the two simply not inter-communicable?
I think that's the $64K question. Do you wait to roll out v6 until you start seeing v6-only hosts start popping up? From an accounting and cost recovery stand point, that probably makes sense in some environments. However, consider the fact that there will be v6 only hosts popping up after IANA/RIR/ISP exhaustion. There will be new entrants in the public internet space that cannot obtain v4 addresses and will be reachable via v6 only. That date is starting to become a bit more predictable too. Those v6 only sites won't be Google or Yahoo, but they will be entrepreneurs with good ideas and new services that your customers will be asking to get access to. We're pursuing a dual stacking model today because we anticipate that the dual-stacking process itself will take a while to deploy, and we want to anticipate customer demand for access to v6 only sites. We could hold off on that deployment, and then spend money on work at the moment of truth, but that approach is not very appealing to us. -- Dan White