Re: tunneling [Was: Agenda for Vienna]

[Pekka Savola <pekkas@netcore.fi>]

On Tue, 20 May 2003, Iljitsch van Beijnum wrote:
> Ok, let me list some solutions that have come up:
> 
> - mobility
> - HIP
> - source routing / conditional source routing
> - controlled deaggregation

- controlled assignment of address space to a class of sites

> - backup path over second ISP using routing or tunnels
> - address agile transports
> - loc/id
> - geo aggregation

HIP is a subset of loc/id, or maybe you mean a different kind of loc-id.
If you're using loc/id to refer to loc/id separation in the network, stop 
abusing the term to apply for that only.

> > Tunneling has certainly been mentioned.  I've always considered
> > this simply a mechanism for virtualizing the topology.  There's
> > effectively still a single address per host, so there's nothing
> > new in addressing.
> 
> After some discussions on the ipv6mh mailinglist we reached the 
> conclusion that rewriting the original source and destination addresses 
> with something else at the source and then replacing the original 
> addresses before the packet is processed at the destination is simply 
> tunneling optimized for header size at the cost of some state. So I 
> guess that makes the loc/id thing a dynamic version of tunneling...

The failure modes are entirely different with rewriting and tunneling.
Consider the case where the state is not fully shared with those who might 
would need it, and the requirements for the devices which must have the 
state.

Tunneling is a very simple thing for intermediaries, and a bit more for 
the end-points (a bit less than rewriting though).

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings