Re: [lisp] WG Last Call draft-ietf-lisp-impact-02

[Ross Callon <[e-mail]>]

The document seems much improved. I still have three issues which should be corrected before the document is ready for publication.


Section 1, last paragraph, second sentence. This currently reads:

    There still are many, economical rather than technical, open questions related to
    the deployment of such infrastructure.

However, it is clear that there are both economical and technical issues. As examples of technical issues, later in the document (section 5.2) talks about the difficulty in troubleshooting, and states "...the major issue that years of LISP experimentation have shown is the difficulty of troubleshooting.  When there is a problem in the network, it is hard to pin-point the reason as the operator only has a partial view of the network". This is of course one example of a technical issue (another related one is my next comment below). Thus I think that it would be correct to change this sentence to state:

    There still are many, economical and technical, open questions related to
    the deployment of such infrastructure.


This might have been lost in the vigorous discussion of other issues which occurred during the first WGLC, however, my comments from the previous WGLC included one point which has not been addressed. This comment was:

> Finally, perhaps I missed it but I didn't see any discussion of the
> volume of overhead related to OAM traffic used for liveness detection
> (the need for ITR's to determine the reachability of ETR's).

I still think that we need discussion of the overhead related to OAM traffic. If this is not known, it might be appropriate simply to add to the second paragraph of section 1 something along the lines of:

    The overhead related to OAM traffic (for example, for liveness detection) is not known.


Also, in section 3, first bullet after the first paragraph, the document currently states:

   o  EID-to-RLOC mappings follow the same prefix size as the current
      BGP routing infrastructure;

In email in our earlier discussion Florin Coras stated:

> The goal our experiments was to understand the
> performance of LISP map-caches if edge
> networks already owning their address space (PI address owners) were to
> switch to LISP. Speculating if and how PA owning edge networks are to
> switch to LISP was outside the scope.

I think that these two points are saying the same thing. However, I am not sure whether most (or all) readers will understand that the bullet point in the current document implies the point that Florin made in his email. We could clarify this in the next paragraph as follows:

OLD
   The above assumptions are inline with [RFC7215] and current LISP
   deployments, however, such situation may change in the long term.
   Nevertheless, [KIF13] and [CDLC] explore different EDI prefix space
   sizes, still showing results that are consitent and equivalent to the
   above assumptions.

NEW
   The above assumptions are in line with [RFC7215] and current LISP
   deployments, however, such situation may change in the long term.
   For example, the first bullet above assumes that only edge networks
   already owning their address space (current PI address owners) will
   switch to LISP. Speculating whether and how PA owning edge networks
   might switch to LISP was outside the scope. Nevertheless, [KIF13] and
   [CDLC] explore different EDI prefix space
   sizes, still showing results that are consistent and equivalent to the
   above assumptions.

Thanks, Ross


From: lisp [mailto:[e-mail]] On Behalf Of Luigi Iannone
Sent: Thursday, May 14, 2015 3:44 PM
To: LISP mailing list list
Cc: Joel Halpern Direct
Subject: [lisp] WG Last Call draft-ietf-lisp-impact-02

Hi All,

the authors of the LISP Impact document  [https://tools.ietf.org/id/draft-ietf-lisp-impact-02.txt]
submitted a new version of the draft and requested the Work Group Last Call.

This email starts a WG Last Call, to end May 28th, 2015.

Please review this updated WG document and let the WG know if you agree that it is ready for handing to the AD.
If you have objections, please state your reasons why, and explain what it would take to address your concerns.

Thanks

Luigi & Joel