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

From: [email-masked] (Noel Chiappa)
Date: Thu, 18 Feb 2010 22:02:23 -0500 (EST)

> From: Robin Whittle <[email-masked]>

    > 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.

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.

	Noel

---

From: Robin Whittle <[email-masked]>
Date: Fri, 19 Feb 2010 15:15:00 +1100

Hi Noel,

> 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.

> 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