Re: [RRG] Consensus? Router-based Translation schemes can only work with duplicate address space

[Robin Whittle <rw@firstpr.com.au>]

Hi Randall,

You wrote:

> While I am impressed with your stamina, I'll save folks time here
> and say that again I disagree with many of the premises that
> you believe.
> 
> - Translation schemes might make packets longer, depending
>   on the design.  Consider IPv4::IPv6 translation for example,
>   where the packet header increases significantly in size.

I was referring to translation schemes for the routing scaling
problem.  The only such scheme I know of is Six/One Router.  One of
the advantages of this is that it does not alter the length of the
packet.


> - We agree that tunnelling has various issues, but they are part
>   of the architectural tradeoffs for the group to evaluate.  All
>   proposed approaches have tradeoffs, as near as I can tell.

OK.


> % This looks like a robust theoretical argument why a router-based
> % translation scheme can never be efficient or robust unless it uses
> % duplicate address space - which means such an approach
> % cannot be practical for IPv4.
> 
> Kindly consider NAT/NAPT/similar devices, which many folks dislike,
> but which continue to be widely deployed and used -- with many
> folks finding the tradeoffs acceptable, the deployment efficient
> enough and robust enough.  These boxes are fundamentally
> translation systems and are a counter-example for your
> bold claim quoted above.

I am only discussing a scheme such as Six/One Router being used
without multiple address spaces.  This is not at all like NAT.  My
example is sufficient to show that the two (three in may example)
communicating hosts have real public addresses, but that these
addresses are not part of the DFZ BGP routing system.  The task of
R1 is to get the packet to the appropriate router R2 for wherever
the destination host's network is currently connected.

If there are other translation schemes which will solve the routing
scaling problem, I hope someone will discuss them.  Likewise, if I
have misunderstood Six/One Router, or if my example is inadequate, I
hope someone will correct me.

 - Robin


--
to unsubscribe send a message to rrg-request@psg.com with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg