Re: [RRG] Separation vs. Elimination

[Michael Meisel <meisel@cs.ucla.edu>]

Hi Tony,

Tony Li wrote:
>  
> 
> |So it seems to me that ESDs are similar to PI addresses (i.e.  GSE  
> |doesn't eliminate the USE of PI addresses, but does get rid of them  
> |in the transit space).  
> 
> 
> This is exactly where I have to disagree.  The ESD is simply not an address.
> It is a wholly orthogonal namespace.  While it is globally unique, it shares
> no other properties with a PI address that I can see.

But it must be used as an address in edge networks, right? How else
would a packet get routed to its final destination host once it gets to
the destination network?

When Lan says "PI address", she's referring in a general sense to an
address that wasn't assigned by your provider. It could certainly come
from a different namespace than PA addresses under a separation scheme,
since the PI addresses are no longer used in core routing. So in this
sense, I would call the ESD a "PI address".

> |How is GSE similar to NAT?
> 
> 
> GSE does pure translation on the routing bits.  In a NAT environment, the
> routing goop is translated into an RFC 1918 address.  In GSE, the routing
> goop gets zeroed out.
> 
> GSE is better than NAT in that it does provide a real identifier that
> applications can now exchange freely, so that much of the translation
> ugliness within NAT (e.g., FTP port commands) can go away.

It seems to me that there is still an important fundamental difference:
when you address a packet to a host behind a NAT, you are addressing the
packet to the routing goop directly. The translation happens only
locally on the destination end (and ugliness results).

With GSE, on the other hand, if you address a packet to a host inside a
GSE network, you are addressing the packet to the ESD, so you need
mapping information (from DNS, in this case) to determine the correct
routing goop.

-Michael

> Tony
> 
> 
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