Re: [v6ops] draft-ietf-v6ops-enterprise-incremental-ipv6 WGLC

Brian E Carpenter <> Tue, 06 August 2013 00:20 UTC

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Date: Tue, 06 Aug 2013 12:20:31 +1200
From: Brian E Carpenter <>
Organization: University of Auckland
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To: Mark ZZZ Smith <>
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Subject: Re: [v6ops] draft-ietf-v6ops-enterprise-incremental-ipv6 WGLC
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On 06/08/2013 09:49, Mark ZZZ Smith wrote:
>> I don't really understand it either. The value I see in ULAs is that it is 
>> your own local address space, meaning that you're in complete charge of it, 
>> unlike the global address space you have been given by somebody else. It seems 
>> to me that one way to increase robustness is to reduce external dependencies. 
>> Using a local address space, that is used in preference to a global address 
>> space when there is a choice, in general should be more robust because you have 
>> absolute control over it.
> Just to clarify though, I'm not for NAT in any form. I think NPT is a lot better, however I still think that because it hides the external identity of hosts from themselves that it creates constraints that are better to avoid. Through experience, I've come to the view point that global uniqueness of identity (through globally unique addresses) is a property that is nearly as important as global reachability for troubleshooting and security.

It seems to me that any IETF consensus document should make it clear
that ULAs are for internal use only, that GUAs should be used in parallel
for external access, and that NPTv6 is (if mentioned) only an experimental

Also note that draft-liu-v6ops-ula-usage-analysis and
draft-liu-v6ops-running-multiple-prefixes are around and cover
this topic.