Re: [Int-area] Fwd: New Version Notification for draft-nordmark-intarea-ippl-01.txt

[Erik Nordmark <[e-mail]>]

On 11/5/15 1:24 AM, Dave Thaler wrote:
>
> I notice that currently RFC 4389 is not referenced at all.
>
> It’s Experimental since there are many ways of proxying and it just 
> describes one of them,
>
> but I still think it bears referencing informatively, especially since 
> section 6 of that RFC is
>
> very relevant to the discussion on loops in the document.
>
Dave,

Sorry for the tardy response. I'll definitely add an explicit reference 
to RFC4389 in the text that currently reads "Hence a NS/NA proxy MUST 
NOT be used with private VLANs."

I don't know if you want some more analysis in the document (in the form 
of an appendix) of why packet proxies don't work.
The short form is that the assumption in RFC4389 is that there is a 
notion of upstream and downstream, but in a PVLAN with multiple routers 
(i.e. promiscuous ports) those ports are peers with no upstream vs. 
downstream notion. Forcing such a notion, e.g., by building a spanning 
tree, would remove the rapid failover and load-balancing benefits that 
motivated having multiple promiscuous ports.

AFAICT this applies to what I'd call "packet proxies" in general. Such 
proxies send a NS (with ttl=255) when receiving a NS.
What we could call "state proxies" do not have such an issue; an example 
of such is DAD proxy (RFC 6957) where a packet received from one host is 
used to build/maintain state which is then used to respond to a NS from 
another host. That approach never emits a NS as a result of receiving an 
NS hence does not have the same looping hazard.

I'll add something along the above lines and submit an update to the draft.

Thanks,
    Erik




> Dave
>
> *From:*Int-area [mailto:[e-mail]] *On Behalf Of *Erik 
> Nordmark
> *Sent:* Tuesday, October 20, 2015 3:39 AM
> *To:* Internet Area <[e-mail]>
> *Subject:* [Int-area] Fwd: New Version Notification for 
> draft-nordmark-intarea-ippl-01.txt
>
> This update adds one more issue about Proxy ARP/ND when there are 
> multiple routers.
>
>    Erik
>
>
> -------- Forwarded Message --------
>
> *Subject: *
>
> 	
>
> New Version Notification for draft-nordmark-intarea-ippl-01.txt
>
> *Date: *
>
> 	
>
> Mon, 19 Oct 2015 11:34:04 -0700
>
> *From: *
>
> 	
>
> [e-mail] <mailto:[e-mail]>
>
> *To: *
>
> 	
>
> Erik Nordmark <[e-mail]> <mailto:[e-mail]>
>
> A new version of I-D, draft-nordmark-intarea-ippl-01.txt
> has been successfully submitted by Erik Nordmark and posted to the
> IETF repository.
> Name:          draft-nordmark-intarea-ippl
> Revision:      01
> Title:         IP over Intentionally Partially Partitioned Links
> Document date: 2015-10-19
> Group:         intarea
> Pages:         11
> URL:https://www.ietf.org/internet-drafts/draft-nordmark-intarea-ippl-01.txt <https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fwww.ietf.org%2finternet-drafts%2fdraft-nordmark-intarea-ippl-01.txt&data=01%7c01%7cdthaler%40microsoft.com%7c8ffc9ba75e0f4c85b95708d2da8f0702%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=zj%2b6dMfG1dO5XaChivn3HhaPj5W3m6ppjqDTmFazqz0%3d>
> Status:https://datatracker.ietf.org/doc/draft-nordmark-intarea-ippl/ 
> <https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fdatatracker.ietf.org%2fdoc%2fdraft-nordmark-intarea-ippl%2f&data=01%7c01%7cdthaler%40microsoft.com%7c8ffc9ba75e0f4c85b95708d2da8f0702%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=wlAdu3Uoe2o%2bYd2c%2fyUAuSDW5GXpxJO2sFnc6zw5s2U%3d>
> Htmlized:https://tools.ietf.org/html/draft-nordmark-intarea-ippl-01 
> <https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2ftools.ietf.org%2fhtml%2fdraft-nordmark-intarea-ippl-01&data=01%7c01%7cdthaler%40microsoft.com%7c8ffc9ba75e0f4c85b95708d2da8f0702%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=1ZE87Hn665vt5%2bmIO%2fRS9JjpIqfaD3x%2fCikCWIikA7o%3d>
> Diff:https://www.ietf.org/rfcdiff?url2=draft-nordmark-intarea-ippl-01 
> <https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fwww.ietf.org%2frfcdiff%3furl2%3ddraft-nordmark-intarea-ippl-01&data=01%7c01%7cdthaler%40microsoft.com%7c8ffc9ba75e0f4c85b95708d2da8f0702%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=OCw2%2fxbBn1NCymhy6snJXV4g%2f2%2bZce3IWtXEC1Ax1xk%3d>
> Abstract:
>     IP makes certain assumptions about the L2 forwarding behavior of a
>     multi-access IP link.  However, there are several forms of
>     intentional partitioning of links ranging from split-horizon to
>     Private VLANs that violate some of those assumptions.  This document
>     specifies that link behavior and how IP handles links with those
>     properties.
>                                                                                    
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at tools.ietf.org.
> The IETF Secretariat
>