Subject: [rbridge] [Editorial Errata Reported] RFC5556 (2532)

From: RFC Errata System <[email-masked]>
Date: Tue, 28 Sep 2010 17:47:15 -0700 (PDT)

The following errata report has been submitted for RFC5556,
"Transparent Interconnection of Lots of Links (TRILL): Problem and Applicability Statement".

--------------------------------------
You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=5556&eid=2532

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Type: Editorial
Reported by: Vishwas Manral <[email-masked]>

Section: 2.4

Original Text
-------------
   When such snooping and optimization is performed by spanning-tree-
   based bridges, it done at each bridge based on the traffic observed
   on that bridge's ports.

Corrected Text
--------------
   When such snooping and optimization is performed by spanning-tree-
   based bridges, it is done at each bridge based on the traffic observed
   on that bridge's ports.

Notes
-----

Instructions:
-------------
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--------------------------------------
RFC5556 (draft-ietf-trill-prob-06)
--------------------------------------
Title               : Transparent Interconnection of Lots of Links (TRILL): Problem and Applicability Statement
Publication Date    : May 2009
Author(s)           : J. Touch, R. Perlman
Category            : INFORMATIONAL
Source              : Transparent Interconnection of Lots of Links
Area                : Internet
Stream              : IETF
Verifying Party     : IESG
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---

From: Donald Eastlake <[email-masked]>
Date: Tue, 28 Sep 2010 21:02:16 -0400

Sure. Looks like a fine minor editorial errata.

Thanks,
Donald

---

From: Eric Gray <[email-masked]>
Date: Wed, 29 Sep 2010 08:09:41 -0400

Donald,

	I disagree.

	Previously, when the statement was difficult to parse, it
at least had the advantage of not being incorrect.  :-)

	There is an issue with inserting "is" (as opposed to - for
instance "may be").  There is not actually a "standard" that is
defined for how snooping is done by any device.  Any device -
including 802.1Q bridges - might choose to be as clever as any
other device in how it performs a non-standard activity.

	There is also the issue with the fact it will now be wrong 
in the sense that - because some subset of the bridges in a LAN 
have a snooping capability - there is no implication that this 
capability is supported in "each" bridge in the LAN.  Hence it 
will not necessarily be the case that "each" bridge does this.

	The text in this section (section 2.4) is extremely fragile
primarily because it is necessary to be delicate in describing a
non-standard activity of protocol entities, especially where the
protocol involved may not be part of the core-expertise of some
subset of the target audience for this text.

	I suggest a different fix.  I suggest changing -

		"it done at each bridge based"

- to one of the following -

		"they commonly base this"

		"these bridges commonly base this"

		"these bridges commonly base the optimization"

In stead of "commonly", you might choose to use "often" or some
similar qualifier.

	At issue is the fact that any such snooping is necessarily
proprietary and may include a possibility that devices may also
use some other proprietary enhancement - or take a different
approach entirely - that allows a correct reaction to changes in 
topology.

	The reason why the approach assumed in this text is one that
is commonly (or often) used is that it does not require additional 
proprietary extensions in order to work "reasonably well."

	In order to clarify relationships between standard 802.1Q
bridges (configured to use some form of STP), the text in this
section would need to be expanded to include a much more complete
explanation of how STP works, and would need to include a survey
of all existing (and possible) implementations of IGMP snooping
(as well as related proprietary enhancements).

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Donald Eastlake
Sent: Tuesday, September 28, 2010 9:02 PM
To: RFC Errata System
Cc: [email-masked]; [email-masked]; [email-masked]; [email-masked]; [email-masked]; [email-masked]
Subject: Re: [rbridge] [Editorial Errata Reported] RFC5556 (2532)

Thanks,
Donald

---

From: Joe Touch <[email-masked]>
Date: Wed, 29 Sep 2010 08:42:06 -0700

Hi, Donald, Eric, and others on the list.

First, this is a good reason why I would prefer if the rfc-editor 
process ignored typographic errata. The cycles spent on this issue are 
already disproportionate to its utility.

On this topic, starting with the corrected text (since there was clearly 
an omission of a single word):

Here's what this was intended to mean (emphasis mine, of course):

	WHEN snooping/optimization is done by conventional bridges,
	that snooping is done within a single bridge based on
	traffic it sees directly on its ports.

I.e., snooping/optimization behavior is NOT the result of inter-bridge 
exchanges about what's best -- the behavior is local.

In this case "each" is meant as the phrase "within a particular individual".

There is already sufficient distinction between "each" and "every", 
where "every" would have indicated that ALL bridges performed 
snooping/optimization.

I see no need to address this errata further; it's fine as it stands 
(and it would have been just as fine to ignore).

Joe

On 9/29/2010 5:09 AM, Eric Gray wrote:
>> Reported by: Vishwas Manral<[email-masked]>
>>
>> Section: 2.4
>>
>> Original Text
>> -------------

---

From: Donald Eastlake <[email-masked]>
Date: Wed, 29 Sep 2010 22:12:54 -0400

Hi Joe,

On Wed, Sep 29, 2010 at 11:42 AM, Joe Touch <[email-masked]> wrote:
> First, this is a good reason why I would prefer if the rfc-editor process
> ignored typographic errata. The cycles spent on this issue are already
> disproportionate to its utility.

Indeed.

> On this topic, starting with the corrected text (since there was clearly an
> omission of a single word):
>

I agree, although it would probably be safer to throw in "usually" or
some similar weasel word.

> There is already sufficient distinction between "each" and "every", where
> "every" would have indicated that ALL bridges performed
> snooping/optimization.
>
> I see no need to address this errata further; it's fine as it stands (and it
> would have been just as fine to ignore).

Thanks,
Donald

>> Cc: [email-masked]; [email-masked]; [email-masked];
>> [email-masked]; [email-masked]; [email-masked]
>>> Title               : Transparent Interconnection of Lots of Links
>>> (TRILL): Problem and Applicability Statement