Re: [lisp] WG Last Call draft-ietf-lisp-impact-01

I understand that the ETR could send a different response to different ITRs. 

However, there is a reason that some more specific prefixes are advertised (in addition to a covering less specific prefix). One reason is that some service providers want incoming traffic delivered to them via different interconnects based on the destination. Even if you are doing traffic engineering with LISP, then this reason doesn't go away, and isn't solved by sending only the less specific prefix in the map reply. Of course there are other reasons to advertise more specific prefixes, and on the most part these don't go away either. I therefore feel that it was an error for the study discussed in [CCD12] to "... filter out more specific prefixes". 

Perhaps a more serious problem is that "BGP-prefix granularity" is not likely to be even remotely close to correct, with or without filtering out more specifics.  

Ross

-----Original Message-----
From: Dino Farinacci [mailto:farinacci@gmail.com] 
Sent: Thursday, April 09, 2015 2:16 PM
To: Darrel Lewis
Cc: Ross Callon; LISP mailing list list; draft-ietf-lisp-impact@tools.ietf.org
Subject: Re: [lisp] WG Last Call draft-ietf-lisp-impact-01

And to add to what Darrel said, the policy control can be provided at the LISP site or by the MSP (Mapping Service Provider). It depends who is jockeying for control or who wants features out-sourced.

Dino

> On Apr 9, 2015, at 10:51 AM, Darrel Lewis (darlewis) <darlewis@cisco.com> wrote:
> 
> 
> On Apr 8, 2015, at 5:29 PM, Ross Callon <rcallon@juniper.net> wrote:
> 
>> My understanding of this is that what some service providers do today is to announce some more specific prefixes (that match a PA prefix assigned to them) at some interconnection points and some different more specific prefixes at other interconnection points in order to draw in traffic where they want to draw it in. If with LISP you were to map all of these prefixes in one mapping table entry then you would be mapping them all to the same RLOC (or set of RLOCs). 
> 
> 
> This is not correct, there is no requirement for an ETR to provide the same answer to one requesting ITR as it does another.  Quite the opposite, replies can be customized depending on many possible variables.
> 
> -Darrel
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