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

Robin Whittle <> Fri, 19 February 2010 04:13 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 4F2D828C12C for <>; Thu, 18 Feb 2010 20:13:22 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.729
X-Spam-Status: No, score=-1.729 tagged_above=-999 required=5 tests=[AWL=0.166, BAYES_00=-2.599, HELO_EQ_AU=0.377, HOST_EQ_AU=0.327]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id amG2z3pqnleo for <>; Thu, 18 Feb 2010 20:13:19 -0800 (PST)
Received: from ( []) by (Postfix) with ESMTP id 3303F28C141 for <>; Thu, 18 Feb 2010 20:13:17 -0800 (PST)
Received: from [] ( []) by (Postfix) with ESMTP id 1EB3E175BEF; Fri, 19 Feb 2010 15:15:02 +1100 (EST)
Message-ID: <>
Date: Fri, 19 Feb 2010 15:15:00 +1100
From: Robin Whittle <>
Organization: First Principles
User-Agent: Thunderbird (Windows/20090812)
MIME-Version: 1.0
References: <>
In-Reply-To: <>
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
Cc: Noel Chiappa <>
Subject: Re: [rrg] LEIDs, SPI & ordinary IP addresses as both IDs & Locs
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: IRTF Routing Research Group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Fri, 19 Feb 2010 04:13:22 -0000

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:
> 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