Re: I-D Action: draft-voyer-6man-extension-header-insertion-07.txt

On Fri, Oct 18, 2019 at 2:23 AM Alexandre Petrescu
<alexandre.petrescu@gmail.com> wrote:
>
>
>
> Le 17/10/2019 à 18:19, Tom Herbert a écrit :
> >
> >
> > On Thu, Oct 17, 2019, 6:20 AM Alexandre Petrescu
> > <alexandre.petrescu@gmail.com <mailto:alexandre.petrescu@gmail.com>> wrote:
> >
> >
> >
> >     Le 15/10/2019 à 00:12, Fernando Gont a écrit :
> >      > On 12/10/19 16:57, Brian E Carpenter wrote:
> >      >> Hi,
> >      >>
> >      >> I'd like to comment on this version. It is in fact a complete
> >      >> rewrite compared to its predecessors and I thank the authors for
> >      >> that. The tone is now purely technical, and that's a great
> >      >> improvement.
> >      >
> >      > It is somewhat frustrating that the draft still fails to argue why
> >      > EH insertion instead of encapsulation.
> >
> >     As usual, I think one of the reasons is a difficulty in qualifying what
> >     it means 'encapsulation'.
> >
> >     There is IP-in-IP encapsulation.
> >
> >     But there is also encapsulation like in transporting, or carrying, by
> >     means of other intermediary headers, layer2, MPLS, security headers and
> >     future internet shims and GRE and routing headers.
> >
> >     IP-in-IP encapsulation is clearly an alternative to EH insertion.
> >
> >     But all the other encapsulations are so messy that one may legitimately
> >     think that a new EH insert/delete standardized according to good WG
> >     principles would be proper, universal, and solve all  problems of GRE
> >     for example.
> >
> >
> > Alex,
> >
> > What are the problems of GRE to which you referring?
>
> Tom,
>
> If I remember correctly, on the negative side, GRE does not work with
> IPsec security, GRE has no IPv6-GRE-IPv6 deployment, GRE is for
> limited-domains and does not work across the Internet contrary to VPN.
>
Alex,

I guess maybe you're only considering GRE/Ethernet, but for GRE/IP I
don't believe any of these negatives are valid. In fact, an IPv6
packet that contains next header 47, a 4 byte GRE header with first 16
bits set to zero and Protocol type set to 0x86dd, followed by an IPv6
packet-- is functionally equivalent to ip6ip6 encapsulation. Also, if
you want to increase the probability of successful traversal through
the Internet then GRE/UDP can be used (RFC8086).

> On the positive side, thanks to its key field, only with GRE it is
> possible to link together several tunnels such as to increase available
> bandwidth by aggregating, whereas with IP-in-IP it is not possible.
>
Yes an advantage of GRE over just ipip encapsulation is that it's
extensible, albeit limited in its extensibility which is why we
developed GUE.

Tom

> Alex
>
> >
> > Tom
> >
> >
> >     Alex
> >
> >      >
> >      >
> >
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