Re: [lisp] Adoption of draft-chiappa-lisp-architecture-01 and draft-chiappa-lisp-introduction-01

jnc@mercury.lcs.mit.edu (Noel Chiappa) Wed, 05 September 2012 13:21 UTC

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Date: Wed, 05 Sep 2012 09:21:21 -0400
From: jnc@mercury.lcs.mit.edu
Cc: jnc@mercury.lcs.mit.edu
Subject: Re: [lisp] Adoption of draft-chiappa-lisp-architecture-01 and draft-chiappa-lisp-introduction-01
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    > From: Ronald Bonica <rbonica@juniper.net>

    > The function of an EID varies depending upon your location ... If you
    > are behind the same ETR as the referenced interface, the EID both
    > locates and identifies the referenced interface. If you are not behind
    > the same ETR as the referenced interface, the EID only identifies the
    > interface.

Yes and no. Ironically, the need to interact with existing hosts means that
in a scope around the 'other' host (more on this in a second), the EID _also_
needs to have some 'routability' - otherwise the packet cannot be forwarded
to the destination.

The size of that scope varies. If the other host is also in a LISP site, it
might reach only to that site's ITR. If the site is a legacy site, connected
directly to the DFZ, there must be a route in the DFZ. Etc, etc.


    > Probably the best that we can do is to point out that the term EID
    > might be a bit of a misnomer.

The "Architectural Perspective" document contains a fairly extensive
discussion of this issue ("5.1. LISP EIDs").

There is a warning cross-reference to that discussion in the "Introduction"
document ("3. LISP Overview"), although I do note that that warning is not
replicated immediately below when the term EID is introduced ("3.1. Basic
Approach").

Would people like to see me add an additional warning (and cross-reference)
at the point at which the term 'EID' is introduced? I don't know if it's
important enough to disturb the flow of the text, but I don't have any
significant objection to so doing if it's important enough.

	Noel