Hi, Scott,

Your comments make sense; I had assumed that "augmented" meant 
that the bytes would be logically prepended to the existing ESP
data before the ICV was calculated, and that this notion was
well-defined wrt existing ESP ICV methods.  I am not as familiar
with the combined mode AAD and how that works, so I'd defer to
your and the authors' judgement on whether additional specification
is needed.

I do agree that the "four" should be changed.  We should also keep
in mind the UDP encapsulation described in section 2.1, which adds
a header of 16 bytes, so we could say, "four, eight, or sixteen".

-Pete

Scott C Moonen wrote:
> Peter, your comment below made me go back and re-read the draft. 
> Section 2.2 of this draft makes this statement: 
> 
>    In the diagrams below, "WESP ICV" refers to the ICV computation as
>    modified by this specification. Namely, the ESP ICV computation is
>    augmented to include the four octets that constitute the WESP
>    header. Otherwise, the ICV computation is as specified by ESP
> [RFC4303]. 
> 
> In general I wonder if this paragraph should be beefed up a bit. 
> Tables 1 and 2 of RFC 4303 go into specific detail as to the order in
> which things are included in the ICV calculation, and simply saying
> "augmented" leaves some ambiguity as to where the WESP data appears. 
> This paragraph should also probably say "four or eight" instead of
> "four".  Finally, I wonder if the document should go into even more
> detail on how the WESP header is authenticated for combined-mode
> algorithms.  Typically those algorithms have "additional
> authentication data", and I wonder if we should document specifically
> how the WESP header appears in the AAD for currently specified
> algorithms, and also document the expectation that future
> combined-mode RFCs should explicitly mention how a WESP header would
> appear in their AAD.            
> 
> 
> Scott Moonen ([email protected])
> z/OS Communications Server TCP/IP Development
> http://www.linkedin.com/in/smoonen
> <http://www.linkedin.com/in/smoonen>  
> 
> 
> 
> From:         "McCann Peter-A001034" <[email protected]>
> To:   <[email protected]>,
> <[email protected]> 
> Cc:   [email protected]
> Date:         12/16/2009 12:20 PM
> Subject:      Re: [IPsec] Gen-ART telechat review of       
> draft-ietf-ipsecme-traffic-visibility-11 
> 
> ________________________________
> 
> 
> 
> 
> I have been selected as the General Area Review Team (Gen-ART)
> reviewer for this draft (for background on Gen-ART, please see
> http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html
> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html>
> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html
> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html> > ).    
> 
> Please wait for direction from your document shepherd or AD before
> posting a new version of the draft. 
> 
> Document: draft-ietf-ipsecme-traffic-visibility-11
> Reviewer: Pete McCann
> Review Date: 16 Dec 2009
> IESG Telechat date: 17 Dec 2009
> 
> Summary: Ready
> 
> Major issues: none
> Minor issues: none
> Nits/editorial comments: none
> 
> This version addresses my previous comment adequately.
> 
> -Pete
> 
> 
> 
> McCann Peter-A001034 wrote:
>> I have been selected as the General Area Review Team (Gen-ART)
>> reviewer for this draft (for background on Gen-ART, please see
>> http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html
>> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html>
>> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html
>> <http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html> > ).  
>> 
>> Please resolve these comments along with any other Last Call comments
>> you may receive.
>> 
>> Document: draft-ietf-ipsecme-traffic-visibility-09
>> Reviewer: Pete McCann
>> Review Date: 2009-10-29
>> IETF LC End Date: 2009-10-28
>> IESG Telechat date: unknown
>> 
>> Summary: One minor issue to discuss
>> 
>> Major issues: none
>> 
>> Minor issues:
>> 
>> Section 2:
>>    As can be seen, the WESP format extends the standard ESP header
>>    by the first 4 octets for IPv4 and by 8 octets for IPv6. The
>>    WESP header is integrity protected, along with all the fields
>>    specified for ESP in RFC 4303.
>> Normally ESP wouldn't need to process encapsulation headers that
>> appear prior to the SPI.  Won't this require modification of the ESP
>> implementation, possibly breaking its modularity?  Would it be
>> problematic for certain algorithms to include this data? It might be
>> good to state that.
>> 
>> Nits/editorial comments: none
> 
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