Re: [RRG] On "jack-down" models

[Brian E Carpenter <brian.e.carpenter@gmail.com>]

On 2008-03-28 09:20, Tony Li wrote:
>  
> 
> |Earlier, Scott Brim wrote:
> |% Specifically how does a network-layer ID make host-based mobility and
> |% multihoming easier?
> |
> |It decouples the TCP/UDP transport session state from the location.
> 
> 
> At the risk of simply summarizing what Pekka and others have said, the key
> point that I'm getting from this is: mobility is aided by having an endpoint
> identifier.  To Scott's question, it need not be in the network layer.  It
> can also exist purely in a session layer, but some identifier is necessary
> so that there can be some continuity of correspondence.  

There was a good reason, I think, why the OSI model included a
recursive approach to namespaces - NSAP addresses were what we
tended to focus on during the IPng debate, but OSI had LSAP addresses
in the link layer, TSAP addresses in the transport layer and SSAP
addresses in the session layer, iirc. By breaking the integrity of
our "NSAP" layer with NATs etc., we've made it very obvious that
we don't have TSAP addresses.

I'm not sure I see a backwards-compatible fix for this lack.

    Brian

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