[Pals] FW: Re-negotiation of support of the PW Status TLV?

Alexander Vainshtein <[email protected]> Tue, 13 May 2025 09:33:41 +0000
Newsgroups gmane.ietf.pwe3
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Forwarding to the correct concluded WG...

Regards,
Sasha

From: Alexander Vainshtein
Sent: Tuesday, May 13, 2025 12:04 PM
To: 'mpls' <[email protected]>
Cc: Andrew G. Malis <[email protected]>; Stewart Bryant <stewart.bryant@gma=
il.com>; [email protected]
Subject: Re-negotiation of support of the PW Status TLV?
Importance: High

Hi all,

I am sending this email to the MPLS WG which presumably will act as the car=
etaker for any open issues pertaining to the scope of the concluded PWE3 WG=
.

Section 6.3.3 of RFC 8077<https://datatracker.ietf.org/doc/html/rfc8077#sec=
tion-6.3.3> says (the relevant text is highlighted):

   When a PW is first set up, the PEs MUST attempt to negotiate the
   usage of the PW Status TLV.  This is accomplished as follows: A PE
   that supports the PW Status TLV MUST include it in the initial Label
   Mapping message following the PW FEC and the Interface Parameter Sub-
   TLVs.  The PW Status TLV will then be used for the lifetime of the
   pseudowire.

This statement is copied  verbatim from Section 5.4.3 of RFC 4447<https://d=
atatracker.ietf.org/doc/html/rfc4447#section-5.4.3>,aAnd these negotiation =
procedures are similar to the procedures of negotiation of the CW usage for=
 PW types for which the CW usage is not mandatory in Section 6.2 of RFC 444=
7.

The negotiation procedures for the CW usage have been modified in RFC 6723 =
and eventually subsumed by Section 7.3 of RFC 8077, so that now CW usage ca=
n be re-negotiated "on the fly" by implementations, that support these modi=
fications.

I wonder whether a similar extension of the PW Status TLV negotiation proce=
dures would be of any interest to the WG.

Your feedback would be highly appreciated,

Regards, and lots of thanks in advance,
Sasha

Disclaimer

This e-mail together with any attachments may contain information of Ribbon=
 Communications Inc. and its Affiliates that is confidential and/or proprie=
tary for the sole use of the intended recipient. Any review, disclosure, re=
liance or distribution by others or forwarding without express permission i=
s strictly prohibited. If you are not the intended recipient, please notify=
 the sender immediately and then delete all copies, including any attachmen=
ts.

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<div class=3D"WordSection1">
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">Forwarding to the c=
orrect concluded WG&#8230;<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<div>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;mso-ligatures:none">=
Regards,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;mso-ligatures:none">=
Sasha<o:p></o:p></span></p>
</div>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<div>
<div style=3D"border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm =
0cm 0cm">
<p class=3D"MsoNormal"><b><span style=3D"font-size:11.0pt;font-family:&quot=
;Calibri&quot;,sans-serif;mso-ligatures:none">From:</span></b><span style=
=3D"font-size:11.0pt;font-family:&quot;Calibri&quot;,sans-serif;mso-ligatur=
es:none"> Alexander Vainshtein
<br>
<b>Sent:</b> Tuesday, May 13, 2025 12:04 PM<br>
<b>To:</b> 'mpls' &lt;[email protected]&gt;<br>
<b>Cc:</b> Andrew G. Malis &lt;[email protected]&gt;; Stewart Bryant &lt;st=
[email protected]&gt;; [email protected]<br>
<b>Subject:</b> Re-negotiation of support of the PW Status TLV?<br>
<b>Importance:</b> High<o:p></o:p></span></p>
</div>
</div>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">Hi all,<o:p></o:p><=
/span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">I am sending this e=
mail to the MPLS WG which presumably will act as the caretaker for any open=
 issues pertaining to the scope of the concluded PWE3 WG.<o:p></o:p></span>=
</p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><a href=3D"https://=
datatracker.ietf.org/doc/html/rfc8077#section-6.3.3">Section 6.3.3 of RFC 8=
077</a> says (the relevant text is
<span style=3D"background:yellow;mso-highlight:yellow">highlighted</span>):=
 <o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;">&nbsp;&nbsp; When a PW is first set up, the PEs MUST attem=
pt to negotiate the<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;">&nbsp;&nbsp; usage of the PW Status TLV.&nbsp; This is acc=
omplished as follows: A PE<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;">&nbsp;&nbsp; that supports the PW Status TLV MUST include =
it in the initial Label<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;">&nbsp;&nbsp; Mapping message following the PW FEC and the =
Interface Parameter Sub-<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;">&nbsp;&nbsp; TLVs.&nbsp;
<span style=3D"background:yellow;mso-highlight:yellow">The PW Status TLV wi=
ll then be used for the lifetime of the<o:p></o:p></span></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Co=
urier New&quot;;background:yellow;mso-highlight:yellow">&nbsp;&nbsp; pseudo=
wire</span><span style=3D"font-size:11.0pt">.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">This statement is c=
opied &nbsp;<i>verbatim</i> from
<a href=3D"https://datatracker.ietf.org/doc/html/rfc4447#section-5.4.3">Sec=
tion 5.4.3 of RFC 4447</a>,aAnd these negotiation procedures are similar to=
 the procedures of negotiation of the CW usage for PW types for which the C=
W usage is not mandatory in Section
 6.2 of RFC 4447.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">The negotiation pro=
cedures for the CW usage have been modified in RFC 6723 and eventually subs=
umed by Section 7.3 of RFC 8077, so that now CW usage can be re-negotiated =
&#8220;on the fly&#8221; by implementations, that
 support these modifications.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">I wonder whether a =
similar extension of the PW Status TLV negotiation procedures would be of a=
ny interest to the WG.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt">Your feedback would=
 be highly appreciated,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt"><o:p>&nbsp;</o:p></=
span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;mso-ligatures:none">=
Regards, and lots of thanks in advance,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;mso-ligatures:none">=
Sasha<o:p></o:p></span></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
</div>


<br><br><p style=3D"font-family: Verdana; font-size:10pt; color:#666666;"><=
b>Disclaimer</b></p><p style=3D"font-family: Verdana; font-size:8pt; color:=
#666666;">This e-mail together with any attachments may contain information=
 of Ribbon Communications Inc. and its Affiliates that is confidential and/=
or proprietary for the sole use of the intended recipient. Any review, disc=
losure, reliance or distribution by others or forwarding without express pe=
rmission is strictly prohibited. If you are not the intended recipient, ple=
ase notify the sender immediately and then delete all copies, including any=
 attachments.
</p></body></html>

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