Re: [v6ops] ULA draft revision #2 Regarding isolated networks

["Liubing (Leo)" <[e-mail]>]

> -----Original Message-----
> From: Brian E Carpenter [mailto:[e-mail]]
> Sent: Tuesday, May 27, 2014 6:40 AM
> To: Mark ZZZ Smith
> Cc: Liubing (Leo); v6ops WG; [e-mail]
> Subject: Re: [v6ops] ULA draft revision #2 Regarding isolated networks
> 
> Mark,
> 
> On 27/05/2014 09:57, Mark ZZZ Smith wrote:
> ...
> >> - "Temporarily isolated" or "Forever isolated". In general, ULAs fit
> >> both cases. Whatever it is temporarily or forever, when
> >> administrators need some prefixes to be on-demand and free to use,
> ULAs are good choice.
> >> However, for the temporarily isolated cases, the administrator needs
> >> to consider once it gets to connected, the hosts might need to be
> >> renumbered; or NAT might be involved if renumbering is not
> >> acceptable. If renumbering or NAT for some reason is considered as
> >> heavy burden, then the administrators need to carefully consider the
> adoption of ULAs.
> >>
> >
> > This paragraph seems to show a fundamental misunderstanding of IPv6's
> multi-addressing capabilities. IPv6 supports multiple concurrent addresses
> (from different prefixes), and can learn new ones or deprecate old ones over
> time. Attachment to a new network doesn't require renumbering, it requires
> propagating new prefixes for the hosts to use in addition to their existing
> ones. Primarily RFC6724 address selection will help the hosts choose the
> right addresses to use as source and destinations when they have multiple
> addresses.
> 
> I didn't read it that way. Of course an IPv6 network runs well with multiple
> prefixes, which is why overlapped renumbering is possible.
> 
> As Fred Baker once pointed out, the real problem is therefore
> *numbering* a network (i.e. adding a new prefix, regardless of whether
> there are zero or more existing prefixes). The text needs to be clear about
> that, for sure.

[Bing] Yes. I considered *numbering a new prefix* as a special kind of *renumbering* in the above texts. I need to make it clear. ULA+GUA is a recommended (we won't use the word in the new version) use case in the current draft. What I need to emphasize should be: the administrators need to consider the operational burden of numbering a new prefix and ensuring the RFC6724 address selection if the isolated network gets connected in the future.

Regards,
Bing

> 
>     Brian