Re: geo short vs long term? [Re: Geo pros and cons]

[Iljitsch van Beijnum <iljitsch@muada.com>]

On donderdag, apr 17, 2003, at 10:29 Europe/Amsterdam, Kurt Erik 
Lindqvist wrote:

> I think the first step still is to define what the options are. Then 
> we can start worry about consensus.
In any multiaddressing scheme, there must be a point where a single 
"handle", be it an address, an FQDN, a control block or what have you, 
is tied to two or more paths through the network. There are many ways 
to do this:

- let the applications handle it (SMTP, DNS)
- let the network layer handle it (MIP)
- let the transport layer handle it (SCTP)
- let a middlebox or border router handle it (MHAP)

GSE isn't easily classified here as transport, network and border 
routers all need to play their part.

I think we can agree that having the applications do it isn't good 
enough for many applications as sessions don't survive a rehoming event.

Network layer has the advantage it is presumably easy to implement.

Transport layer has the advantage that it already has the end-to-end 
state which makes failover easier and doesn't pollute the architecture 
by introducing state elsewhere.

Middlebox/border router has the advantage the number of boxes that need 
to be upgraded is very small.

These are our basic choices. The problem is that each of the advantages 
and disadvantages will be appreciated differently by different users. 
Enterprise users want central policy control, home users and mobile 
users want flexibility no no reliance on provider cooperation. Some 
people need multihoming in IPv6 yesterday, others haven't even heard of 
IPv6 in the first place.

If possible, I think the best choice is not to choose at all, but make 
the mechanism generic enough that it can work anywhere.