[v6ops] Comments on draft-ietf-v6ops-ipv6-ehs-packet-drops-01

[Gorry Fairhurst <[e-mail]>]

I promised a  careful read of this ID at the last v6OPS meeting, and 
this is it.

* First, I think this is a useful document to help understand what is 
happening in operational networks and reasons for this. It's also a 
ueseful input for planning standards actions in 6man, etc. Thanks for 
doing this.

* I have some concerns that some of the choices of words could 
(unintentionally) be taken as endorsing a best practice, which I don't 
think the IETF would generally promote. This is more about ensuring 
specific parts can not be quoted out of context. I did a careful read 
and hope I identified most of these and propose something that might be 
helpful (please see attached PDF - RTF is identical). I think it would 
be good to clarify in a few places this is the RFC8200 spec, since I 
have heard there could be new work to update that.

* On the measurement evidence: I have  a slight concern that the results 
might not cover the wide variety of use cases and you may like to be 
more careful in the words you use to generalise these for the 
"internet".  I think we should be aware that in some scenarios an EH 
might still be effectively used, where path can safely support this. In 
some other uses, the fact that packets with these options might be 
expected to be dropped by many paths - for good reasons, does not mean 
that the option is useless to set in general - it might merely be that 
for these paths it is not possible to use the option and then care is 
needed in deciding which packets set the EH and how this is used.

Hope this helps, Fernando. If you need any clarification or other help, 
just let me know,

Gorry

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