Re: [IPsec] IANA ikev2 registry and FC values

[Yaron Sheffer <[e-mail]>]

I agree that sharing registries with related but different protocols is 
not a good thing. I just think this is not one of these cases.

Thanks,
	Yaron

On 01/17/2013 08:13 PM, Tero Kivinen wrote:
> Yaron Sheffer writes:
>> OTOH your proposal would mean one more difference between "regular"
>> IPsec implementations and FC-specific ones. I don't think that would be
>> a good thing.
>
> FC-specific ones are only using these non-truncated ones, and they are
> using special ID payloads, separate protocol ID values, different
> types of traffic selectors etc. They are reusing the basic IKEv2
> protocol, and some of the payloads, but it is different protocol than
> IKEv2.
>
>>> They are not defined for IP use at all. None of the IKEv2/ESP over IP
>>> uses those values. Ah, found text from our IPsec/IKE Roadmap:
>>>
>>> 		   For HMAC-SHA-1 and HMAC-MD5, the IKEv2 IANA registry
>>>      contains values for both the truncated version and the standard non-
>>>      truncated version; thus, IKEv2 has the capability to negotiate either
>>>      version of the algorithm.  However, only the truncated version is
>>>      used for IKEv2 SAs and for IPsec SAs.  The non-truncated version is
>>>      reserved for use by the Fibre Channel protocol [RFC4595].  For the
>>>      other algorithms (AES-XCBC, HMAC-SHA-256/384/512, AES-CMAC, and HMAC-
>>>      RIPEMD), only the truncated version can be used for both IKEv2 and
>>>      IPsec-v3 SAs.
>>>
>>> which actually says we always use truncated version (so I was wrong
>>> they are not forbidden anywhere, missed this text last time as it uses
>>> SHA-1 spelling not SHA1, which I was searching for :-).
>>>
>>
>> This text is simply describing the existing situation. It is not at all
>> normative.
>
> Which is why I also want to describe that existing situation in the
> IANA registry. If you want to use those non-truncated versions in
> IPsec, you can write draft describing that...
>
>>> That is true, and I do not consider that as a good thing. It is much
>>> better to have one good way of doing things than two ways of doing
>>> same thing, especially if those two ways are about the same.
>>>
>>
>> Yes, but people have good reasons to add algorithms, which is (part of
>> the reason) why we negotiate them in the protocol. Thus "Tiger",
>> "camellia" and the like, and I'm sure the FC folks had a good reason for
>> the untruncated algorithms, too.
>
> They had some reason, but on the other hand IPsec people did not want
> those untruncated algorithms, and have not specified them for IP use.
> This is one of the problems when sharing registries causes problems.
> Suddenly you might have options for protocols which did not request
> them added to them, because someone else who shares the same registry
> added them.
>