Subject: [lisp] LISP basic questions

From: Damian <[email-masked]>
Date: Mon, 18 Jul 2011 10:59:09 +0200

Hi ML,

I am trying to understand the concept of LISP and would like to pose some
questions, if that is okay.

Who exactly is supposed to run and configure ETRs and ITRs? In my
understanding it is those organizations, who participate in global BGP
routing, so basically those with their own ASes? What about smaller
organizations who have their own RIPE-registered IP-net but are just one
of many networks in a larger AS? I suppose, it does not make sense for
such smaller organizations to set up their own ETRs/ITRs to serve the
original purpose, as it wouldn't offload the Internet's global BGP table.

Nevertheless, there are other benefits for smaller companies which run
multiple sites. Site-to-site routing could be balanced for instance, if
each site was multi-homed and multiple ETRs per site were available. I
wonder however, what will happen if someone invests in several Nexus 7000
to leverage those benefits today, and some time later the AS owning
provider has plans to set up his own LISP-infrastructure. Won't there be a
problem with double-encap or similar?

Best Regards
 Damian

---

From: Lori Jakab <[email-masked]>
Date: Mon, 18 Jul 2011 15:16:36 +0200

Damian,

> problem with double-encap or similar?

Double-encap was taken into account in the design of LISP, and the
scenario you describe will be possible. For the encapsulations on the
different levels you can use different mapping systems, so for example
on the first level you keep using your company's mapping system and the
AS border routers would use the global mapping system.

You just have to be careful to avoid MTU problems.

Regards,
-Lori

> Best Regards
>  Damian
>
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