Re: RFC 8200: The Devil's Paragraph

On Sat, 29 Feb 2020 at 07:44, Manfredi (US), Albert E
<albert.e.manfredi@boeing.com> wrote:
>
> Ron Bonica <rbonica=40juniper.net@dmarc.ietf.org> wrote:
>
> > "Extension headers cannot be added to a packet after it has left the its source node and extension headers cannot be removed from a packet until it has arrived at its ultimate destination".
>
> Which is the way I always interpreted the paragraph. The word "processed" I guess causes problems, although I'm not sure if they are real, or just people trying to get away with something.
>
> For what it's worth, in this case where the "penultimate node" must do something strange, before the packet can be delivered to its intended destination, my own approach has always been to address the packet TO THE PENULTIMATE NODE, and then that router knows what to do with it.

Yes.

I'm wondering what the value is of leaving the outer IPv6 tunnel
header there is after the SRHectomy.

If the outer IPv6 tunnel header (with a DA of the "penultimate node")
and the SRH and every other EH for the "penultimate node" were
processed and removed at that node, leaving the original inner IPv6
packet to be then sent on, we'd have an operation as old as the hills
known as "decapsulation".

> This violates nothing. Given that the "penultimate node" has to be specifically configured for this job anyway, it doesn't seem like such an approach limits flexibility or anything else. (Unless I missed something critically imnportant in the long thread.)
>
> Bert
>
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