Re: [rrg] LEIDs, SPI & ordinary IP addresses as both IDs & Locs

[Robin Whittle <[e-mail]>]

Hi Noel,

You wrote:

>> I am sure that the LEID always has Locator semantics. How else does a
>> packet with a LEID in its destination field get delivered reliably to
>> the correct destination host, from anywhere in the world?
> 
> Not all LISP packets have an LEID in the destination field. (I'm talking here
> about packets between a LISP host and a legacy host. For packets between two
> LISP hosts, they _never_ appear outside the sites with a LEID anywhere in the
> outer header.) See:
> 
>   http://tools.ietf.org/id/draft-lewis-lisp-interworking-02.txt
> 
> and in particular, Section 6.

I was only discussing packets with LISP EID addresses in their
destination field.  I wasn't discussing packets sent to hosts on
ordinary (non LISP EID) addresses.

> But I get what I assume to be your basic point, that in packets to legacy
> hosts, depending on exacly which interoperability mechanism is in use, in some
> cases the LEIDs may have more complex semantics.

I don't understand your reply at all.  My message did not concern
"packets to legacy hosts".

I was only discussing packets being sent to LEID addresses - no matter
whether they were sent by a "legacy" host or a LISP host.

My point was that a LEID address always has Locator semantics, and that
so does every other global unicast IP address.  Its just that if the
LEID destination address is for a host in a network different from that
of the sending host, then for part of the journey to the destination
host, the LEID address has its Locator semantics interpreted by a new
"Algorithm 2", which ITRs execute.

  - Robin