Subject: Re: New draft: Now What?

From: S Woodside <[email-masked]>
Date: Fri, 2 May 2003 13:34:21 -0400

Hi, I have a comment about this draft from the perspective of Community 
wireless networks.

> 3.1.1. Minimal
>
>    Very minimal end-sites, such as typical home networks or very small
>    enterprises, are quite small and typically do not include mission-
>    critical activities.

Yes, this is true.

>    Naturally, anyone would be willing to achieve multihoming benefits,
>    but usually the associated costs, e.g. caused by obtaining physical
>    connectivity to two ISPs, do not justify it.

This is a argument that begs the question "is it expensive". You are 
assuming that the answer is yes, but it's not with a CWN, one of the 
main points of a CWN is to share bandwidth from people connected to 
different ISPs. That's different people, each individually connected to 
one ISP, but sharing the traffic between them, in a mesh, or a managed 
network, whatever, they are still sharing it.

Simon

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From: Pekka Savola <[email-masked]>
Date: Fri, 2 May 2003 23:35:56 +0300 (EEST)

> network, whatever, they are still sharing it.

Well, actually the "expensive" factor not real for e.g. many SOHO users.  
Getting two DSL lines from different providers costs you double the 20-40$ 
(or whatever).  Not a big deal.  A problem is that they typically go via 
the same telco phone lines, so it doesn't really add any L1-L2 redundancy.  
Using Cable+DSL might be more failure-proof though.

However, I'd argue such CWN's could classify themselves as "Small" sites.

The terminology and drawing the line is a bit shaky, unfortunately.

But the point of the draft basically is that anything of the size "small" 
(or maybe even "large") or smaller, we *have* to go with multiple PA 
addresses or stick with multi-connecting, IMHO.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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From: Pekka Savola <[email-masked]>
Date: Wed, 7 May 2003 00:25:33 +0300 (EEST)

Hi,

Anyone (else S Woodside :-) had time to read my "roadmap" document yet?
http://www.ietf.org/internet-drafts/draft-savola-multi6-nowwhat-00.txt

I'd be very interesteded in receiving feedback on it.

In particular, the document classifies the sites in 4 different 
categories, and makes a hypothesis on their multihoming requirements, 
like:

                        .--------------.------------.--------------.
                        | Independence | Redundancy | Load sharing |
         .--------------+--------------+------------+--------------+
         |Minimal       |      no      |     no     |      no      |
         |Small         |    maybe     |    maybe   |      no      |
         |Large         |  maybe/yes   |     yes    |     maybe    |
         |International |     yes      |     yes    |      yes     |
         '--------------'--------------'------------'--------------'

* Do the classifications seem close to reality? 
* Does the hypothesis on their typical requirements seem to be close to 
the mark?

As one another point that was raised was a way forward; basically, a short 
term goal being on multi-connecting, host-centric multihoming, multihoming 
at site exit routers and a PI-based addressing for the "International" and 
possibly even some "Large" site classifications.

An alternative to PI-based addressing might be a different concept of 
breaking such big "sites" into smaller pieces.

* Do these immediate/short term goals seem reasonable?
* Are there some short-term goals which I've missed?
* Do folks think that we need a PI-based (de facto) addressing/multihoming 
solutions for a class of sites (think "Cisco", "Nokia", "IBM", etc.)?
* Do folks think that actually defining a border between those which could 
use PI-based addressing and those who couldn't would be possible?
* Do folks agree that we should continue the work with host-centric 
multihoming/multihoming at site-exit routers -type solutions?  There 
missing pieces there (ingress filtering, tunneling overhead with RFC3178, 
etc.)

Some food for thought... 

On Fri, 25 Apr 2003, Pekka Savola wrote:
> As promised, here's a new draft which has been partially extracted from my 
> MSc (also plugged in here earlier):
> 
> http://www.netcore.fi/pekkas/ietf/draft-savola-multi6-nowwhat-00.txt
> 
> (It has also been submitted to the I-D repository, and will probably
> appear next week -- but I know you guys like spending time reading drafts
> during the weekend, so here we go.. :-)
> 
> In particular the goal is to make us able to focus our thoughts a bit and 
> try to break the site multihoming into a bit smaller pieces.
> 
> It's 15 pages; the abstract is below.  Have fun.
> 
> Abstract
> 
>    ROUTING ARCHITECT'S WARNING: flagrant IPv4 site multihoming practices
>    cause a significant increase the routing table size, change rates and
>    instability, the tragedy of the commons by encouraging selfish
>    routing practices, the exhaustion of the 16-bit AS number space, and
>    may collapse the Internet interdomain routing architecture.
> 
>    As there has been a desire to avoid similar problems as seen with
>    IPv4, the use of similar techniques to achieve site multihoming has
>    been prevented operationally in IPv6.  However, the long effort to
>    proceed with other IPv6 multihoming mechanisms has produced lots of
>    heat but little light.  This memo tries to list available techniques,
>    split the organizations to different types to separately examine
>    their multihoming needs, to look at the immediate and short-term
>    solutions for these organization types, and to list a few immediate
>    action items on how to proceed with IPv6 site multihoming.
> 
>

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From: S Woodside <[email-masked]>
Date: Wed, 7 May 2003 14:58:31 -0400

I'm confused though. This is the site multihoming WG, so does a single 
host, or let's say, a single home qualify as a site?

I'll continue to harp on the CWN angle since I think I've found the 
right IETF area ;-) Load sharing is a requirement for multihoming CWN 
nodes. It would be good to get that into the internet architecture 
instead of having to create something special to CWNs to handle it. 
Also IIRC another person mentioned the PAN, where you might have WiFi 
and GPRS connections, where does that fall into your taxonomy?

simon

--
www.simonwoodside.com -- 99% Devil, 1% Angel

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From: Pekka Savola <[email-masked]>
Date: Thu, 8 May 2003 09:14:23 +0300 (EEST)

> host, or let's say, a single home qualify as a site?

A degenerate case of site is a single host.  In particular, "home 
networks" are considered sites.

All of these fall within my "Minimal" category.
 
> instead of having to create something special to CWNs to handle it. 

Could you elaborate on the specific load sharing needs, how it's done now, 
etc. because this seems very surprising to me.

> and GPRS connections, where does that fall into your taxonomy?

I'm not sure what you refer to.

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From: S Woodside <[email-masked]>
Date: Mon, 12 May 2003 20:01:49 -0400

> etc. because this seems very surprising to me.

Load sharing: people want to join the CWN to use the aggregate upstream 
bandwidth of the CWN nodes. Even if it's just me and my neighbour, the 
ability for me to use the bandwidth from my DSL and his cable at the 
same time is desired. (Yes ... I know I can't bond the links ...)

<digression>
CWN Multihoming, currently it's not done. - The MeshAP in Knightsbridge 
and generally systems based on the locustworld system select the 
closest internet gateway in the mesh and use that one. Routing inside 
the mesh is with AODV. It's probably the most advanced CWN today.  - 
SeattleWireless uses squid to proxy network connections for gateway 
owners who want to share their bandwidth. They know they want it. They 
just don't know how to do it.
</digression>

> I'm not sure what you refer to.

Let me outline a hypothetical situation. I have a PB titanium, it's a 
new one, with bluetooth, and WiFi, and I have a bluetooth phone with a 
GPRS connection. I'm at the office so my pb can connect either with 
Wifi to the corporate network to the intranet only, or with GPRS to the 
public internet. Is that challenging enough? ;-)

simon

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From: Pekka Savola <[email-masked]>
Date: Tue, 13 May 2003 08:55:05 +0300 (EEST)

> same time is desired. (Yes ... I know I can't bond the links ...)

Which addresses do the CWN nodes configure in the DNS?  E.g. if I have a 
BSD box sitting there as my personal home router, and it has DNS records, 
which of them are used for that?

I would imagine it's today done with NAT, if it's possible..

Or is the direction of the load-sharing strictly out-bound? (which is less 
of a problem.)

> just don't know how to do it.

Interesting -- even though a bit more research-oriented than "mainstream"
multihoming.
 
> public internet. Is that challenging enough? ;-)

Well, PB+phone could be considered as a small site of its own, but for 
most intents and purposes, it seems to act similarly as a single node.

This issue seems similar in some ways to the case where a company (a site) 
provides ADSL access to its employees' homes.  Are those homes (where 
there might be more than one node, even more than one subnet) sites too?  
What if the home also has a "regular" Internet access?

These are tough questions, and I don't have the answers, unfortunately.  
:-) Multihoming with multiple connections and multiple addresses should
work, though.