Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses)

Owen DeLong owen at delong.com
Sun Oct 31 16:31:47 UTC 2010


On Oct 31, 2010, at 7:22 AM, Valdis.Kletnieks at vt.edu wrote:

> On Thu, 21 Oct 2010 19:21:41 PDT, George Bonser said:
> 
>> With v6, while changing prefixes is easy for some gear, other gear is
>> not so easy.  If you number your entire network in Provider A's space,
>> you might have more trouble renumbering into Provider B's space because
>> now you have to change your DHCP ranges, probably visit printers, fax
>> machines, wireless gateways, etc. and renumber those, etc.  And some
>> production boxes that you might have in the office data center are
>> probably best left at a static IP address, particularly if they are
>> fronted by a load balancer where their IP is manually configured.
> 
> "If Woody had gone straight to a ULA prefix, this would never have happened..."
> 
Or better yet, if Woody had gone straight to PI, he wouldn't have this problem,
either.

> If a site is numbering their internal IPv4 stuff to avoid having to renumber
> on a provider change, then why would they number their IPv6 stuff from
> provider space rather than ULA space?
> 
Which gains what vs. PI?

> And remember - (a) IPv6 allows machine to easily support multiple addresses and
> (b) if you have  a provider address and a ULA, changing providers only means
> renumbering a *partial* renumber of the hosts that require external visibility
> - your internal hosts can continue talking to each other on a ULA as if nothing
> happened.
> 
If you have PI space, changing providers can be even easier and you can leave
multiple providers running in parallel.

Owen





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