RE: 6MAN Adoption call on raft-chakrabarti-nordmark-6man-efficient-nd-04

I also do support the adoption of the draft
Maria Rita

-----Original Message-----
From: ipv6 [mailto:ipv6-bounces@ietf.org] On Behalf Of Suresh Krishnan
Sent: Thursday, November 21, 2013 3:56 PM
To: Eric Levy- Abegnoli (elevyabe)
Cc: 6man Chairs; 6man WG
Subject: RE: 6MAN Adoption call on raft-chakrabarti-nordmark-6man-efficient-nd-04

I support the adoption of this draft.

Thanks
Suresh

----- Original Message -----
From: "Eric Levy- Abegnoli (elevyabe)" <elevyabe@cisco.com>
To: Ole Troan <otroan@employees.org>, 6man WG <ipv6@ietf.org>
Cc: 6man Chairs <6man-chairs@tools.ietf.org>
Sent: 11/21/2013 3:20 AM
Subject: Re: 6MAN Adoption call on raft-chakrabarti-nordmark-6man-efficient-nd-04

Hi,
I support this draft: besides the operational value already mentioned, I can see all the cool things we would be able to do, to scale up the number of node on the link.

Broadcasting on the link is quite fine when you have a limited number of addresses to deal with, and the dynamic is low. But we plan for layer-2 networks much bigger and much more dynamic (industrial, datacenter, very large campus) and broadcasting + caching is creating a bottleneck.

I imagine we could also do routing with a cache instead of a table, and broadcast queries to find the destination prefix. Everybody would agree it does not scale. It's not just the numbers; it's also the dynamic.

I ran a simple math: 100,000 nodes, 3 addresses each, 10% of nodes moving every minute (moves can be physical or virtual), 3 multicast messages sent per move (DAD, NA, MLD), message size could go from 100B to 1KB (when using CGA for instance), that would range from 1 Mbit to 8 Mbit/sec.
Definitely an issue for the wireless links, but not only.
Last but not least, there is quite a bit of latency involved when looking for a target that is not in cache.

A cache is a good response to these problems, as long as the dynamic is low. But it's just a cache: when numbers grow, it can't keep up.  And it¹s not designed to be distributed.
Registration and dissemination (this draft, and sail-draft) propose a shift to a more pro-active approach, "a la" routing. Any node looking for an address on-link will either have it in its table (not cache) or will know who have it (that's the distribution part).
The critical piece is not just registration; it's also distribution so that the information is available quickly where it's needed, along the forwarding path.

There is a lot to clarify though: co-existence with the legacy model, distribution scheme (hierarchical, hash-based, Š), nature of the registrars (Routers? Switches? DHCP servers? Š).

Eric

On 19/11/13 11:45, "Ole Troan" <otroan@employees.org> wrote:

>All,
>
>There was moderate support to adopt this draft at the working group 
>meeting in Vancouver.
>This is an adoption call to confirm the result of the hum at the meeting.
>
>Please provide a view with reasons as to whether the WG should adopt 
>this or not.
>
>This message starts a one week 6MAN Working Group call on adopting:
>
>    Title           : Wired and Wireless IPv6 Neighbor Discovery
>Optimizations
>    Author(s)    : S. Chakrabarti, E. Nordmark, P. Thubert, M. Wasserman
>    Filename    : draft-chakrabarti-nordmark-6man-efficient-nd-04
>    Pages        : 31
>    Date          : 2013-10-22
>
>
>http://tools.ietf.org/html/draft-chakrabarti-nordmark-6man-efficient-nd
>-04
>
>The call ends on November 26th, 2013.
>
>Regards,
>
>Bob Hinden & Ole Trøan
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