[ih] Some Questions over IPv4 Ownership

[Scott Brim]

On 10/15/2010 12:08 EDT, Jorge Amodio wrote:
>> It's all store-and-forward, and the forwarding step uses whatever
>> external information the forwarder can glean.  A difference is the
>> routing mechanism.  (Typical) Internet routing gathers information in
>> advance because it has to forward its packets fast (and suffers when
>> reality doesn't match the information it has gathered), while mailers
>> have a nice mapping system built for them called DNS that they use on
>> demand.
> 
> I always thought email routing as end-to-end, if you take a message as
> a single data unit that message will be delivered (in theory) to
> whatever host has the MX record for the destination domain, instead IP
> packets are routed on a hop by hop basis with a chance of routing
> dynamically changing when the packet left the source and is in
> transit.
> 
> I don't see further forwarding by the receiving MX host as "routing".
> 
> -J

Check out "layer networks" in ITU-T G.805 and following.  Email routing
is hop-by-hop within its layer network context.