Re: [Gen-art] Gen-ART review of draft-atlas-icmp-unnumbered-08

[Carlos Pignataro <[e-mail]>]

[adding JR to Cc:]

On 12/27/2009 6:02 PM, [e-mail] wrote:
> And the draft needs a new email address for JR:

Yes, we will fix this before publication.

Thanks again,

-- Carlos.

> 
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>       Subject:	Gen-ART review of draft-atlas-icmp-unnumbered-08
>       Sent:	12/27/2009 5:53 PM
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> 
> Thanks,
> --David
> 
> 
>> -----Original Message-----
>> From: Black, David
>> Sent: Sunday, December 27, 2009 5:53 PM
>> To: [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
>> '[e-mail]'
>> Cc: Jari Arkko; Black, David
>> Subject: Gen-ART review of draft-atlas-icmp-unnumbered-08
>>
>> 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).
>>
>> Please resolve these comments along with any other Last Call
>> comments you may receive.
>>
>> Document: draft-atlas-icmp-unnumbered-08
>> Reviewer: David L. Black
>> Review Date: December 27, 2009
>> IETF LC End Date: January 1, 2010
>>
>> Summary:
>> This draft is on the right track, but has open issues, described
>> in the review.
>>
>> Comments:
>> The draft defines an extension to ICMP messages that allows additional
>> network interface information to be provided with some ICMP messages.
>> The information may be an ifIndex, an IP address, an Interface Name
>> and/or an MTU.
>>
>> The one open issue in this review involves the use of ifIndex to
>> identify an interface.  The motivating use cases in section 3
>> involve traceroute, ACL-caused-blockage, and the need to determine the
>> MTU - those use cases are "public" in the sense that they clearly
>> encompass use of the ICMP messages by other than the network operator
>> whose device generated those messages.
>>
>> In this context, IP address, Interface Name and MTU are all clearly
>> useful, but I am concerned about ifIndex.  An ifIndex is effectively
>> private to the SNMP management infrastructure of the network operator.
>> Determining what interface an ifIndex designates generally involves
>> SNMP access that a network operator may be reluctant to grant to
>> outsiders due to the level of detail that such access may expose.
>>
>> I suspect that the ifIndex could be *very* useful to an ifIndex-
>> enhanced traceroute issued from a network operator's management
> station
>> as alluded to in paragraphs 3-5 of Section 6 (Security
> Considerations).
>> My open issue is that I should have to go all the way down to the
> latter
>> part of the Security Considerations section in order to find the
>> motivations for and intended usage of one of the major features of
> this
>> extension.
>>
>> I suggest adding a Section 3.3 to discuss use of ifIndex with ICMP and
>> network management tools (e.g., enhanced traceroute plus an SNMP
> manager)
>> by a network operator to debug his/her own network.  This new section
>> should also contain some sort of warning that ifIndex information may
>> not be available to other than the network operator's management
>> applications (with a pointer to the Security Considerations section).
>>
>> Nits:
>> - Section 2: "o  that interface is numbered"  Please add a definition
>> 	of "numbered" for an interface.
>> - Section 4.1: Explain what a C-Type is.  A few words and a reference
>> 	to Section 8 of RFC 4884 should suffice.
>> - Section 5.4: This appears to be poorly stated:
>>    A single instance of IP Address information MAY be included only in
>>    the following circumstances:
>>
>>    Included in what?  I presume an Interface Information Object.
> Also,
>>    MAY ... only is poor usage of RFC 2119 terminology.  Here's an
> attempt
>>    at better phrasing:
>>
>>    When an Interface Information Object contains an IP Address, one of
>>    the following two conditions MUST be true:
>>
>> idnits 2.11.15 did not find any nits.
>>
>> Thanks,
>> --David
>> ----------------------------------------------------
>> David L. Black, Distinguished Engineer
>> EMC Corporation, 176 South St., Hopkinton, MA  01748
>> [phone]             FAX: [phone]
>> [e-mail]        Mobile: [phone]
>> ----------------------------------------------------
>