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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>My general comment is that this draft does
a lot of unneeded bad-mouthing of Spanning tree and indirectly of IEEE. There are
a lot of brilliant folks at IEEE that have devoted many years of their life to
improve spanning tree and to make it the only current deployed protocol at
layer 2. If spanning tree was as bad as described in this draft it will not be
currently deployed.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Let’s make the point for TRILL, but
be fair: to prove that TRILL is a good idea it is enough to mention that TRILL
is capable of using all the links In a network while spanning tree is not.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I ask the authors to remove all the
statement detrimental to Spanning Tree and limit the discussion to the
advantages of the TRILL approach.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Since we are in 2008, I suggest the
authors to remove all the mentions of Thickcable, Thincable and hubs: these
things no longer exist.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>My detailed comments:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>ABSTRACT<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Please rewrite from scratch.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Please remove reference to “custom routing
protocols”. Not clear what they are.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>There is no route propagation at layer 2.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Routing is a layer 3 term, IEEE 802.1 never
speaks about routing.<o:p></o:p></span></font></p>
<pre><font size=2 color=navy face=Arial><span style='font-size:10.0pt;
font-family:Arial;color:navy'>Not clear what “</span></font>convergence of these routing protocols and stability under link <o:p></o:p></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> changes and failures is also of concern” means<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>INTRODUCTION<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>“convergence of the spanning tree protocol can be slow.” This has been addressed by RSTP.<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>2.0 THE TRILL PROBLEM<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>Remove citation to Thicknet and Thinet: no longer relevant.<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>Not clear what it means: “The spanning tree configuration is <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> affected by even small topology changes, and small changes can have <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> large effects. Each of these inefficiencies can cause problems for <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> current link layer deployments. “<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>2.1. Inefficient Paths<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>Remove reference to “hub”: no longer relevants and not relevants for this discussion.<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>2.3 Convergence and safety<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>This is absolutely not correct: “if RSTP is in use, <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> produce persistent loops lasting for tens of seconds due to BPDU <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> traffic throttling [5].”<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>Spanning tree is not unsafe: “All variants of spanning tree are inherently unsafe”<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>2.5. Other Ethernet Extensions <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>802.1 is not an “Ethernet Extension”<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>802.1w, 802.1s, 802.1v no longer exist: they have been incorporated in 802.1Q.<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>3.3. Forwarding <st1:place
w:st="on">Loop</st1:place> Mitigation <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>There are no transient loops in Spanning Tree<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>3.4. Spanning Tree Management <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>Sections 2.2 and Error! Reference source not <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> found.)<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>4 Applicability<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>It seems original that being almost done with TRILL, we still have a sentence that says: “A currently open question is …”<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>-- Silvano<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'> <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='margin-left:36.0pt;text-align:center'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal style='margin-left:36.0pt'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
rbridge-bounces@postel.org [mailto:rbridge-bounces@postel.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Donald Eastlake<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, July 01, 2008 8:07
PM<br>
<b><span style='font-weight:bold'>To:</span></b> rbridge@postel.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [rbridge] WG LC
draft-ietf-trill-prob-04.txt</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Hi,<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>This message initiates a
two week TRILL Working Group Last Call on the draft below.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Thanks,<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:0pt;margin-right:0pt;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Donald and Erik<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>2008/6/27 <<a
href="mailto:Internet-Drafts@ietf.org" target="_blank">Internet-Drafts@ietf.org</a>>:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0pt;margin-right:0pt;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>A New Internet-Draft is available from the on-line
Internet-Drafts directories.<br>
This draft is a work item of the Transparent Interconnection of Lots of Links
Working Group of the IETF.<br>
<br>
<br>
Title :
Transparent Interconnection of Lots of Links (TRILL): Problem and Applicability
Statement<br>
Author(s) : J. Touch, R.
Perlman<br>
Filename :
draft-ietf-trill-prob-04.txt<br>
Pages : 18<br>
Date :
2008-06-27<br>
<br>
Current Ethernet (802.1) link layers use custom routing protocols<br>
that have a number of challenges. These routing protocols need to<br>
strictly avoid loops, even temporary loops during route propagation,<br>
<br>
<br>
because of the lack of header loop detection support. Routing tends<br>
not to take full advantage of alternate paths, or even non-<br>
overlapping pairwise paths (in the case of spanning trees). The<br>
convergence of these routing protocols and stability under link<br>
changes and failures is also of concern. This document addresses<br>
these concerns and suggests that they are related to the need to be<br>
able to apply modern network layer routing protocols at the link<br>
layer. This document assumes that solutions would not address issues<br>
of scalability beyond that of existing bridged (802.1) links, but<br>
that a solution would be backward compatible with 802.1, including<br>
hubs, bridges, and their existing plug-and-play capabilities.<br>
<br>
This document is a work in progress; we invite you to participate on<br>
the mailing list at <a href="http://www.postel.org/rbridge" target="_blank">http://www.postel.org/rbridge</a><br>
<br>
A URL for this Internet-Draft is:<br>
<a href="http://www.ietf.org/internet-drafts/draft-ietf-trill-prob-04.txt"
target="_blank">http://www.ietf.org/internet-drafts/draft-ietf-trill-prob-04.txt</a><br>
<br>
Internet-Drafts are also available by anonymous FTP at:<br>
<a href="ftp://ftp.ietf.org/internet-drafts/" target="_blank">ftp://ftp.ietf.org/internet-drafts/</a><br>
<br>
Below is the data which will enable a MIME compliant mail reader<br>
implementation to automatically retrieve the ASCII version of the<br>
Internet-Draft.<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
=============================<br>
Donald E. Eastlake 3rd<br>
<st1:Street w:st="on"><st1:address w:st="on">155 Beaver Street</st1:address></st1:Street><br>
<st1:place w:st="on"><st1:City w:st="on">Milford</st1:City>, <st1:State w:st="on">MA</st1:State>
<st1:PostalCode w:st="on">01757</st1:PostalCode> <st1:country-region w:st="on">USA</st1:country-region></st1:place><br>
<a href="mailto:d3e3e3@gmail.com" target="_blank">d3e3e3@gmail.com</a> <o:p></o:p></span></font></p>
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