RE: [EXT] Re: Last Call: <draft-ietf-6man-rfc2460bis-08.txt> (Internet Protocol, Version 6 (IPv6) Specification) to Internet Standard

[David Mozes <[e-mail]>]

Hi * ,
I am also supporting the insertion of in-band telemetry like INT along with the  actual data packet .
It is for sure a valid use case for the modern networking including data center. 
There are several proposals how to embedded telemetry information   some of them are with in nvo3 tannling protocols 
(Vxlan-GPE,Geneve) Spring and other  . 
I think that ipv6 hbh is the "cleanest"  way to add such info.
	1) I don't see any and advantages on the other  proposals (NVO3 ,SPRING) over IPV6 hbh.
	2))As far as security In the IPsec community, AH is pretty much considered deprecated, a failed experiment.They  are  prefer to use   ESP for authentication as well.
 
The postal system and the letter is very nice e example  . I will treat the adding ipv6-hbh info as stamps on the envelops ,since we are not touching  the data gram itself just the envelope

Thx
David
-----Original Message-----
From: ipv6 [mailto:[e-mail]] On Behalf Of Tal Mizrahi
Sent: Tuesday, February 14, 2017 3:37 PM
To: Mark Smith <[e-mail]>
Cc: [e-mail]; [e-mail]; IETF Discussion list <[e-mail]>; [e-mail]
Subject: RE: [EXT] Re: Last Call: <draft-ietf-6man-rfc2460bis-08.txt> (Internet Protocol, Version 6 (IPv6) Specification) to Internet Standard

Hi Mark,

I certainly agree that hop-by-hop insertion/modification introduces potential security vulnerabilities.
Therefore, as I pointed out below, I would recommend to tackle this by defining something along the lines of “Hop-by-hop extensions can be inserted/removed/modified/processed by intermediate nodes *if* [……..] and the possible consequences are [……..]”

For example, hop-by-hop handling can be restricted only to a single administrative domain, or only to tunnels (as in the zero checksum case). 

Regards,
Tal.

>-----Original Message-----
>From: Mark Smith [mailto:[e-mail]]
>Sent: Monday, February 13, 2017 6:07 PM
>To: Tal Mizrahi
>Cc: [e-mail]; IETF Discussion list; draft-ietf-6man- 
>[e-mail]; [e-mail]
>Subject: [EXT] Re: Last Call: <draft-ietf-6man-rfc2460bis-08.txt> 
>(Internet Protocol, Version 6 (IPv6) Specification) to Internet 
>Standard
>
>External Email
>
>----------------------------------------------------------------------
>Hi,
>
>
>
>On 14 February 2017 at 00:43, Tal Mizrahi <[e-mail]> wrote:
>> Hi,
>>
>>
>>
>> Good discussion regarding the text about the hop-by-hop extension.
>>
>>
>>
>> In my opinion there is a valid use case for intermediate nodes that 
>> insert/remove/modify/process hop-by-hop extensions. Examples: IOAM, INT.
>>
>> Since there is a use case, I believe we need explicit text about 
>> intermediate handling of hop-by-hop extensions.
>>
>
>
>Imagine you sent a letter through the postal system, and the postal 
>system wanted to add information to that letter, that is then to be 
>removed before the letter arrives at its final destination.
>
>The postal system have at least two choices as to how to add that information.
>They could:
>
>(a) unstick your envelope's seal, insert the information, reseal the 
>envelope so well you can't tell and send it on its way, some how 
>flagging to a destination device within the postal system that this 
>specific envelop needs to be openned, a specific page removed, and then resealed.
>
>(b) take a new envelope with new internal postal system source and 
>destination address information, insert your letter without touching it 
>in addition to the new information, and then sending it on its way.
>
>Imagine that the information to be added by the postal system is 
>printed on the same type of paper and is written in the same font as 
>you've chosen to use to write your letter.
>
>Have a think about these two methods, what could fail with each of 
>them, and what the consequences may be if any of those failures occur.
>Have a think of the benefits of each method, and whether they're worth 
>it compared to the failure mode costs and consequences for the method.
>
>>
>>
>> This [somewhat] reminds me of the discussion a few years ago about 
>> the IPv6/UDP zero checksum. The WG ended up defining that “Zero 
>> checksum is permitted in IPv6/UDP *if* [……..] and the possible consequences are [……..]”.
>>
>>
>
>That is a far more trivial change to the packet - it is allowing a 
>value in an existing field that was formerly prohibited, and nodes that 
>did not understand that value would drop the packet because that is 
>what they had been specified to do if they received this prohibited value. In other words, existing implementations '
>behaviour when this formerly unexpected value was encountered had 
>already been specified and deployed.
>
>
>>
>> I would argue that regarding hop-by-hop extension handling we also 
>> need to define that “Hop-by-hop extensions can be 
>> inserted/removed/modified/processed by intermediate nodes *if* [……..] 
>> and the possible consequences are [……..]”.
>>
>
>Some things that are possible to do in theory shouldn't be done in 
>practice, because the consequences when their implementations fail can 
>be severe and outweigh the benefits.
>
>In theory, inserted EHs will be removed 100% of the time. In practice 
>they won't be, because implementations can have bugs and they can also 
>fail in unexpected ways e.g., hardware faults.
>
>Regards,
>Mark.
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