Frequently-Asked-Questions.md
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+## Why are you using monotone for the registry? Why not GIT?
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+There is an important difference between the data model of monotone and GIT: In GIT branches *are* HEADs, while in monotone, branches are a list of HEADs. Or, to state it simpler and probably less correct: It is possible to sync merge conflicts in monotone. In GIT, conflicts are part of the index and/or working tree, and thus can't be pushed/pulled.
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+The DN42 registry is stored on multiple monotone servers which sync with each other. This is not possible in GIT, because the GIT servers don't know how to handle merge conflicts. In monotone, the servers just sync the conflict.
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+## What about IPv6 in DN42?
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+There are some ASes in DN42 that route IPv6 traffic. It is not yet agreed upon what prefixes should be used. The following proposals are the more sane ones:
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+* Use Site-Local-Addresses (SLAs, also known as Unique Local Addresses, ULAs). This is the *fd00::/8* range. In theory, this would be the obvious winner of this debate. They were standardised for exactly this purpose (not publicly routed networks that still want to use unique prefixes). Sadly, this would require you to announce two prefixes in your LAN if you want to use stateless autoconfiguration and no NAT: The SLA and a globally routed prefix. It is not yet clear if this really works. The relevant RFCs about source address selection demand a behavior that would make this work at the moment (until globally routed addresses from 8000::/1 are used)
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+* Use your globally routed PA space. This fixes the LAN-issue, because you only need to announce a single prefix.
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+(*TODO*)
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+At the moment, it is probably save to say that everyone doing IPv6 routing accepts at least prefixes from fd00::/8 with prefix lengths between 48 and 64 bits (inclusive) if they are part of the registry.